Re: Ideas for a simple, but somewhat extendable computer bus

[emanuel stiebler via cctalk]

On 2017-11-17 18:11, Jim Brain via cctalk wrote:
I'm currently working on a single board computer system, designing from 
scratch partially as an education experience, and also as something that 
might be of interest to others.


I've laid out the first version of the SBC, and I realize it would cost 
nothing to add an edge connector on the PCB, allowing expansion 
options.  As well, assuming the design has any merit, I can see creating 
one of these SBcs for each family (8080/Z80, 65XX, 68XX, and maybe even 
16 bit options like TMS9900, 68K, etc.)


You know this projects?

https://en.wikipedia.org/wiki/N8VEM

Re: Drive capacity names (Was: WTB: HP-85 16k RAM Module and HPIB Floppy Drive

[Chuck Guzis via cctalk]

On 11/17/2017 09:17 AM, allison via cctech wrote:

> Also the Syquest 270mb IDE/parallel port cartridge disk.  I have one
> that works
> and over a dozen carts.  Its still in use in a ITX box using the IDE
> interface.  After
> two decades of use it seems solid.

I've left out the non-floppy technologies.   I have a Squest Sparq,
unused still in its packaging, for example.  After being sent one for
evaluation, I rejected it because it was offered only in the
printer-port version, which necessarily limits transfer bandwidth.

But there were plenty of "floppy" technologies, such as the UHD144, or
LS120 or Drivetec stuff.   I treat Bernoulli and Zip as a floppy-sort-of
technology, because they are incapable of reading standard floppies, so
I don't include them either, even though they employed flexible media.

--Chuck

Re: Ideas for a simple, but somewhat extendable computer bus

[Chuck Guzis via cctalk]

On 11/17/2017 06:33 PM, ben via cctalk wrote:

> Say USB-version 101101100 :)

No, I'm serious--lowers parts count tremendously.  I run SPI at 40 MHz.

But for something simpler in a parallel bus there's always STD bus, or
STD-32.

--Chuck

Re: Manchester University Joint System in the 1970s

[Jarratt RMA via cctalk]

I was there 1980-1984, I don't ever recall using a 7600 though, I thought I used
a CDC Cyber 172 (or 170 or something similar). It is possible I may have some
records buried at home, but I am away at the moment and they would not be easily
accessible. I have to re-arrange a lot of stuff over Christmas so I will keep a
lookout.


However, *I* have a question for *you*. For the last year I have been working on
building an emulator for MU5 (see https://robs-old-computers.com/projects/mu5/).
Do you have *any* information at all about MU5? I am particularly short on
anything about the operating system, MUSS.


Thanks


Rob

> 
> On 17 November 2017 at 17:24 Peter Allan via cctalk
>  wrote:
> 
> 
> I was a student at Manchester University from 1974 to 1980. During that
> time I used the University of Manchester Regional Computer Centre (UMRCC)
> computer system. The so-called Joint System consisted of a CDC 7600 with
> an
> ICL 1906A front end. We used to submit card decks via a Systime (a PDP-11
> clone, I believe) that functioned as a remote job entry service.
> 
> I am trying to find out information about the structure of those card
> decks
> (mine were used for shopping lists years ago), and in particular, what the
> first card in the deck was that routed the job to the correct computer.
> 
> I have found information about JOB cards for both ICL computers running
> George 3 and for the CDC 7600 running SCOPE 2.1 (which is what the
> computers ran), but I believe that neither of these gives the full story
> about what we used on the Joint System.
> 
> Does anyone who used this system, or similar ones in the UK, recall
> anything relevant?
> 
> If you have suggestions about where else to post this query, I would be
> grateful for that too.
> 
> Cheers
> 
> Peter Allan
> 

Re: Ideas for a simple, but somewhat extendable computer bus

[allison via cctalk]

On 11/17/2017 08:11 PM, Jim Brain via cctalk wrote:
> I'm currently working on a single board computer system, designing
> from scratch partially as an education experience, and also as
> something that might be of interest to others.
>
> I've laid out the first version of the SBC, and I realize it would
> cost nothing to add an edge connector on the PCB, allowing expansion
> options.  As well, assuming the design has any merit, I can see
> creating one of these SBcs for each family (8080/Z80, 65XX, 68XX, and
> maybe even 16 bit options like TMS9900, 68K, etc.)
>
 A bus that can accommodate 8/16 and also IO mapped plus memory mapped
peripherals forces a
lot of bus logic or interface logic.  The Current winner that has had
all of those is S100-IEEE-696
and its messy.

The more you try to cram into it the more complex it must be, or the
interface from each SBC is so
constrained they can easily share memory or IO in their natural form
(ex: 16bitter reading 8 bit ram will be slow).

At a minimum make 8 and 16it exclusive or your bus interfacs have high
overhead.   Also take into account that not
all cpus mix well or play well in a multicpu mix.

> However, as the design is not *for* any purpose, and I've never
> designed a bus that could be shared among multiple CPUs, I am
> wondering what bus layout would satisfy the following criteria:
>
>  * At least enough to support a traditional 8 bit CPU (A0-15,D0-7,
>    RESET, READ/WRITE,CLOCK,INTERRUPTS) with potentially a few more
>    address bits (A16-23)
>  * Minimal number of bus signals to support multi-processors and
>    peripheral cards, but not so few that usefulness is severely crippled
>  
Mread, Mwrite, IOread IOwrite, Eread (early),  Ewrite (Early write)

Then you need a set of bus-request, bus-available signals.

And signals to indicate an 8 or 16 bit read or write (Bhi, Blow) or
byte/word
for IO and memory...

Interrupts each differs and few overlap.

Bottom line if your teaching multi-cpus make the bus as simple as
possible as you then
are not locked to explaining how a 8bitter lives on a 16bit bus or the
other way around.

> * Easy to implement (minimize need for logic that serves to solely
>    handle the bus)
More un-alike stuff on the bus the harder it gets.

>  * (If 16 bit data bus is part of the design): Easy for 8 and 16 bit
>    CPUs and peripherals to share the bus (Maybe this means 16 bit units
>    need to be constrained to 8 bit, not sure)

>  * Works out to a size that I can buy edge connectors cheaply (62 pin
>    .100" connectors are looking like my cheap option at present)
>

simple 16 data, 24 address likely 6 lines for basic control plus others
your up to 50+ lines and
you may want interleaved grounds and also doubled DC pins for current
capability and more
for multiple voltages.  is 62 enough?   Look at ISA-8 for an answer.

> I looked at home computer busses (Atari, Apple, Commodore, Tandy, TI)
> for a bit of inspiration, but they all seem overly simplistic (not
> horrible, but hate to just punt on the idea).  I also looked at the
> ISA bus and the S-100 bus, but they are a bit overwhelming to me (I
> can grok all the signals, but ensuring they are all responsive seems
> like it will drive more logic be on the PCB jsut to handle the bus,
> and I am trying to keep costs very minimal).
>

Easy limit the possible mixed set of CPUs. 

   in the 8bit realm that mix well are 8085, Z80, Z180, 8088.   The
other set would be the 6502/6800/6809 group.
  Mixing 6502 and z80 is messy or 6502 with 8088 more of same.

 Adding in the 16bit takes the need for bus translation and timing
between 8bit or 16 bit peripherals.

 Mixing 6500 and z80 are annoying as z80(and 8080, 8085,8088) do IO in
separate space from
memory there 6500/6800/6809 peripheral IO is in memory space.  Sure you
can force the issue with logic
or make the z80 do io in memory space for simple convenience but for
those cpus that is atypical.

The single fastest way to limit cost is limit the possible cpu flavors. 
for example ts fairly trivial to make
8085, 8088 and z80 present similar signals to a common bus.

Most of the machine mentioned were at best single cpu (Atari, Apple,
Commodore, Tandy, TI) and many were
not well executed.  FYI TI 9900 is both 16bit and serial as the LRU
interface is bit addressed serial and
very unique perpierals.

> Thus,
>
> Is there a bus (or a fraction of a bus standard) that I should
> consider to accommodate the above?  Anyone else interested in this
> idea and in a collaborative mood?
>

All depends.  IF your trying share peripherals and memory you end up
with S100 or S100 like.  If you trying to
talk to each other than maybe something like GPIB or SCSI (or a flavor
of those) may suit the need.  Or simple
network bus serial or parallel.  The latter can be few in wires but
imposes a protocal to talk from A to B
and may make putting memory (not mass storage) in it awkward.

I did this years ago with 8085/z80/8088 and that ended up sorta like 

Re: Drive capacity names (Was: WTB: HP-85 16k RAM Module and HPIB Floppy Drive

[allison via cctalk]

On 11/16/2017 03:30 PM, Geoffrey Reed via cctech wrote:
>
> On 11/15/17, 9:44 AM, "cctalk on behalf of Fred Cisin via cctalk"
>  wrote:
>> Can you name another 20 exceptions?   (Chuck and Tony probably can)
>>
>>
>> --
>> Grumpy Ol' Fred  ci...@xenosoft.com
>
>  ³Floptical² disks 720 rpm 1.6 Mb/s transfer 1250 TPI and 25MB unformatted
> capacity
>
>  LS-120 and LS-240 (which sadly I can¹t remember the specs of :(
>
>
>

Also the Syquest 270mb IDE/parallel port cartridge disk.  I have one
that works
and over a dozen carts.  Its still in use in a ITX box using the IDE
interface.  After
two decades of use it seems solid.

Allison

Re: Ideas for a simple, but somewhat extendable computer bus

[Charles Anthony via cctalk]

On Fri, Nov 17, 2017 at 5:11 PM, Jim Brain via cctalk  wrote:

> I'm currently working on a single board computer system, designing from
> scratch partially as an education experience, and also as something that
> might be of interest to others.
>
>
I don't know how complex the logic is, but VME bus springs to mind:
https://en.wikipedia.org/wiki/VMEbus

96 pins
32 bit data
32 bit address
Has bus arbitration for multiple CPUs
Existing hardware


>
>
>

Re: Ideas for a simple, but somewhat extendable computer bus

[Toby Thain via cctalk]

On 2017-11-17 8:55 PM, Jon Elson via cctalk wrote:
> On 11/17/2017 07:34 PM, Jim Brain via cctalk wrote:
>> On 11/17/2017 7:25 PM, Paul Koning wrote:
>>>
>>> One key question is whether it should be asynchronous, as the Unibus
>>> is, or synchronous.
>> I thought synchronous would make for a smaller/simpler design, but
>> could be wrong.
>>> A synchronous version of the Unibus would be quite easy; all the
>>> ...
>> It does not have to be fast.  I rather thought, "what is the simplest
>> multi-cpu shared bus that could be easily understood by folks and
>> allow them to focus on multi-processing education, not bus understanding"
>>
>> Jim
>>
>>
> You might also take a look at Multibus and VME, if you just want to see
> how others did it.

For a nice survey of buses, including those two: "Digital Bus Handbook",
Joseph di Giacomo.

https://dl.acm.org/citation.cfm?id=83494

> 
> Jon
> 

Re: Ideas for a simple, but somewhat extendable computer bus

[ben via cctalk]

On 11/17/2017 6:59 PM, Chuck Guzis via cctalk wrote:

On 11/17/2017 05:34 PM, Jim Brain via cctalk wrote:


It does not have to be fast.  I rather thought, "what is the simplest
multi-cpu shared bus that could be easily understood by folks and allow
them to focus on multi-processing education, not bus understanding"


How about a serial bus?  Physically simple and not too awful logically
today.  Say, I2C or SPI...

--Chuck


Say USB-version 101101100 :)

I would say use a 68000 if your still can get them,
but run with a 6800 style clock. The master CPU and
shared memory on the high phase of the clock. The
slave CPU's on the low clock PHASE (clocked by a inverted clock).
This will give you multi-processing with a bit more than
64KB.
Ben.

Re: Ideas for a simple, but somewhat extendable computer bus

[Chuck Guzis via cctalk]

On 11/17/2017 05:34 PM, Jim Brain via cctalk wrote:

> It does not have to be fast.  I rather thought, "what is the simplest
> multi-cpu shared bus that could be easily understood by folks and allow
> them to focus on multi-processing education, not bus understanding"

How about a serial bus?  Physically simple and not too awful logically
today.  Say, I2C or SPI...

--Chuck

Re: Ideas for a simple, but somewhat extendable computer bus

[Jon Elson via cctalk]

On 11/17/2017 07:34 PM, Jim Brain via cctalk wrote:

On 11/17/2017 7:25 PM, Paul Koning wrote:


One key question is whether it should be asynchronous, as 
the Unibus is, or synchronous.
I thought synchronous would make for a smaller/simpler 
design, but could be wrong.
A synchronous version of the Unibus would be quite easy; 
all the funny one-shot delays would disappear and actions 
would simply be taken on the clock edge (rising or 
falling, pick one).  Just make the clock period 
comfortably longer than the worst case propagation delay 
and you're in business.
Given the CPU landscape, I am thinking < 10MHz, which 
would seem to satisfy the criteria.


I'm assuming it doesn't need to be all that fast.  If you 
clock period > prop delay is an issue, things get vastly 
more complicated.  If so, you might want to stick with 
something that's already been sorted out, like PCIe.
It does not have to be fast.  I rather thought, "what is 
the simplest multi-cpu shared bus that could be easily 
understood by folks and allow them to focus on 
multi-processing education, not bus understanding"


Jim


You might also take a look at Multibus and VME, if you just 
want to see how others did it.


Jon

Re: Ideas for a simple, but somewhat extendable computer bus

[william degnan via cctalk]

On Nov 17, 2017 8:34 PM, "Jim Brain via cctalk" 
wrote:
>
> On 11/17/2017 7:25 PM, Paul Koning wrote:
>>
>>
>> One key question is whether it should be asynchronous, as the Unibus is,
or synchronous.
>
> I thought synchronous would make for a smaller/simpler design, but could
be wrong.
>
>> A synchronous version of the Unibus would be quite easy; all the funny
one-shot delays would disappear and actions would simply be taken on the
clock edge (rising or falling, pick one).  Just make the clock period
comfortably longer than the worst case propagation delay and you're in
business.
>
> Given the CPU landscape, I am thinking < 10MHz, which would seem to
satisfy the criteria.
>
>>
>> I'm assuming it doesn't need to be all that fast.  If you clock period >
prop delay is an issue, things get vastly more complicated.  If so, you
might want to stick with something that's already been sorted out, like
PCIe.
>
> It does not have to be fast.  I rather thought, "what is the simplest
multi-cpu shared bus that could be easily understood by folks and allow
them to focus on multi-processing education, not bus understanding"
>
> Jim
>

Not simpler but there were S100 systems with those cpus, except maybe the
TI 16.

Bill Degnan
twitter: billdeg
vintagecomputer.net

Re: Ideas for a simple, but somewhat extendable computer bus

[Jim Brain via cctalk]

On 11/17/2017 7:25 PM, Paul Koning wrote:


One key question is whether it should be asynchronous, as the Unibus is, or 
synchronous.
I thought synchronous would make for a smaller/simpler design, but could 
be wrong.

A synchronous version of the Unibus would be quite easy; all the funny one-shot 
delays would disappear and actions would simply be taken on the clock edge 
(rising or falling, pick one).  Just make the clock period comfortably longer 
than the worst case propagation delay and you're in business.
Given the CPU landscape, I am thinking < 10MHz, which would seem to 
satisfy the criteria.


I'm assuming it doesn't need to be all that fast.  If you clock period > prop 
delay is an issue, things get vastly more complicated.  If so, you might want to 
stick with something that's already been sorted out, like PCIe.
It does not have to be fast.  I rather thought, "what is the simplest 
multi-cpu shared bus that could be easily understood by folks and allow 
them to focus on multi-processing education, not bus understanding"


Jim

Re: Ideas for a simple, but somewhat extendable computer bus

[Paul Koning via cctalk]

> On Nov 17, 2017, at 8:11 PM, Jim Brain via cctalk  
> wrote:
> 
> I'm currently working on a single board computer system, designing from 
> scratch partially as an education experience, and also as something that 
> might be of interest to others.
> 
> I've laid out the first version of the SBC, and I realize it would cost 
> nothing to add an edge connector on the PCB, allowing expansion options.  As 
> well, assuming the design has any merit, I can see creating one of these SBcs 
> for each family (8080/Z80, 65XX, 68XX, and maybe even 16 bit options like 
> TMS9900, 68K, etc.)
> 
> However, as the design is not *for* any purpose, and I've never designed a 
> bus that could be shared among multiple CPUs, I am wondering what bus layout 
> would satisfy the following criteria: ...

You might start with the Unibus and make some small tweaks.  If you think of 
each of the several CPUs as a DMA device, which asks for the bus and gets the 
grant from a central arbiter, you've got your MP bus right there.  Strip out 
some unneeded stuff, like multiple interrupt levels (if you want).

One key question is whether it should be asynchronous, as the Unibus is, or 
synchronous.  If you put a central clock on the bus also (presumably from the 
arbiter since there's one of those) everything else gets a whole lot simpler.  
There are good reasons for the Unibus to be async, but if you can do sync 
that's a much better choice.

A synchronous version of the Unibus would be quite easy; all the funny one-shot 
delays would disappear and actions would simply be taken on the clock edge 
(rising or falling, pick one).  Just make the clock period comfortably longer 
than the worst case propagation delay and you're in business.

I'm assuming it doesn't need to be all that fast.  If you clock period > prop 
delay is an issue, things get vastly more complicated.  If so, you might want 
to stick with something that's already been sorted out, like PCIe.

paul

Ideas for a simple, but somewhat extendable computer bus

[Jim Brain via cctalk]

I'm currently working on a single board computer system, designing from 
scratch partially as an education experience, and also as something that 
might be of interest to others.


I've laid out the first version of the SBC, and I realize it would cost 
nothing to add an edge connector on the PCB, allowing expansion 
options.  As well, assuming the design has any merit, I can see creating 
one of these SBcs for each family (8080/Z80, 65XX, 68XX, and maybe even 
16 bit options like TMS9900, 68K, etc.)


However, as the design is not *for* any purpose, and I've never designed 
a bus that could be shared among multiple CPUs, I am wondering what bus 
layout would satisfy the following criteria:


 * At least enough to support a traditional 8 bit CPU (A0-15,D0-7,
   RESET, READ/WRITE,CLOCK,INTERRUPTS) with potentially a few more
   address bits (A16-23)
 * Minimal number of bus signals to support multi-processors and
   peripheral cards, but not so few that usefulness is severely crippled
 * Easy to implement (minimize need for logic that serves to solely
   handle the bus)
 * (If 16 bit data bus is part of the design): Easy for 8 and 16 bit
   CPUs and peripherals to share the bus (Maybe this means 16 bit units
   need to be constrained to 8 bit, not sure)
 * Works out to a size that I can buy edge connectors cheaply (62 pin
   .100" connectors are looking like my cheap option at present)

I looked at home computer busses (Atari, Apple, Commodore, Tandy, TI) 
for a bit of inspiration, but they all seem overly simplistic (not 
horrible, but hate to just punt on the idea).  I also looked at the ISA 
bus and the S-100 bus, but they are a bit overwhelming to me (I can grok 
all the signals, but ensuring they are all responsive seems like it will 
drive more logic be on the PCB jsut to handle the bus, and I am trying 
to keep costs very minimal).


Thus,

Is there a bus (or a fraction of a bus standard) that I should consider 
to accommodate the above?  Anyone else interested in this idea and in a 
collaborative mood?


Jim

--
Jim Brain
br...@jbrain.com
www.jbrain.com

Re: Manchester University Joint System in the 1970s

[Charles Anthony via cctalk]

On Fri, Nov 17, 2017 at 9:24 AM, Peter Allan via cctalk <
cctalk@classiccmp.org> wrote:

> I was a student at Manchester University from 1974 to 1980.
> If you have suggestions about where else to post this query, I would be
> grateful for that too.
>
>
Contact the University Library, check to see if they have the local user's
guides from that period in the collection?

-- Charles

Re: Playing with HP2640B

[Mattis Lind via cctalk]

> Wow!  Excellent job Mattis  
> I have seen that HP2640 when it still was in bad shape. The HP2640,
> that I have, has many tiny spots on the screen. Your “result after”
> really looks fantastic.


Thanks Henk! I have a few more screens that need fixing. The most difficult
will be the Tek 4016. So I need to do some practice before that one.


> What’s not clear to me, after removing the old “protection” sheet, did
> you apply some new “protection” sheet, or leave the tube “as-is” ?
> I doubt whether that “protection” sheet would really help much if
> the tube would implode (for whatever miraculous reason) …


No, I didn't add anything between the crt and the glass. If it actually is
a protective shield then of course there is not at all the same protection
afterwards. But as Christian Corti mentioned it might just be an etched
glass to remove reflections.  I know at the RICM when doing the same thing
on a DEC VR14 they added a sheet of lexan between the crt and the glass. I
think Michael Thompson can tell more about this.


>
> Henk
>

/Mattis

RE: Playing with HP2640B

[Henk Gooijen via cctalk]

Van: Mattis Lind via cctalk
Verzonden: vrijdag 17 november 2017 11:52
Aan: David Collins; General Discussion: 
On-Topic and Off-Topic Posts
Onderwerp: Re: Playing with HP2640B

The screen on my HP2640 had degenerated quite far. It was only a spot in
the middle, 2 by 4 inch, that still attached the glass to the CRT. I used a
thin fish fillet knife to dig through the remaining glue.

Before

https://scontent-arn2-1.xx.fbcdn.net/v/t1.0-9/23622163_10155696765784985_6518064439030378363_n.jpg?oh=44cbf7f7f00d6e25155c208124e20a38=5AA7349D

The result after:

https://scontent-arn2-1.xx.fbcdn.net/v/t1.0-9/23621971_10155696757184985_1959733265676657917_n.jpg?oh=36a20689c0fb5a16de7fc4df138a40e0=5A9993B1


Anyhow, I researched the glue a bit. The glue is, as far as I understand,
PVAc (PolyVinylAcetate, sometimes also known as PVA). PVAc is not soluble
in water. It takes quite high temperature to melt it. However PVAc is
soluble in many esters. I bought some Butylacetate. It dissolves sample
bits of glue from HP2640 quite well and rapidly. Butylacetate has quite
high boiling temperature (about 120 degrees centigrade) and thus does not
evaporate that quickly. So my idea is now to test on a 2645 screen or VR201
screen by adding some butylacetate and seal with some thin plastic wrap
foil and let it dissolve a bit. Then use the fish fillet knife again and
repeat the process.

/Mattis


Wow!  Excellent job Mattis  
I have seen that HP2640 when it still was in bad shape. The HP2640,
that I have, has many tiny spots on the screen. Your “result after”
really looks fantastic.
What’s not clear to me, after removing the old “protection” sheet, did
you apply some new “protection” sheet, or leave the tube “as-is” ?
I doubt whether that “protection” sheet would really help much if
the tube would implode (for whatever miraculous reason) …

Henk

Re: DR-DOS

[Tomasz Rola via cctalk]

On Fri, Nov 17, 2017 at 02:30:20PM +0100, Liam Proven via cctalk wrote:
> I hope this is vintage enough.
[...]
> VBox mounts that. But it won't boot, nor in VMware  -- it just
> displays 2 dots and freezes.
> 
> Embarrassingly late in the troubleshooting process, I've found why.
> 
> I didn't think to check what was on the image! Foolish of me.
> 
> I mounted it on a pre-booted VM and looked, and it's blank! There's
> nothing in the image at all.
> 
> So, I mounted the empty image file as a loop device, copied the boot
> files in there and then the rest of the files in the distro archive.
> 
> And lo, it works! It boots my VM just fine, and it's now running 7.01-08.

Please excuse me if my remark is unnecessary, but if I read you right,
you have: 

1. Downloaded "empty" disk image - which apparently boots enough to
display two dots

2. Copied system (DOS) files on it (say, from backup)

3. You have not erased the boot-sector-from-the-i-net? So it is there
and still boots the (now fully functional) DOS?

If so, perhaps you should start over from totally new, empty image?
Not copy from your currently working image, but from your backup. Just
in case. Or at least try to disassemble the boot sector to see what it
is doing (I have no idea how, but somehow it must be possible).

"Things" can escape from VMs. I have plenty of Xen warnings and bug
descriptions in my old mailboxes, chances are there will be more.

> All I need to do now is work out how to make the hard disk bootable,
> and I'm in business.

Boot some other OS, (I am partial to GRML Linux, well packed with
rescue stuff and more - https://grml.org/ ); + fdisk, mark bootable?

> The DR-DOS 7 SYS command won't do it, as the files aren't named
> IBMBIOS.COM and IBMSYS.COM -- they're DRBIO.SYS and DRSYS.SYS.
> 
> I copied them to the expected names. SYS completes but the disk won't boot.

Perhaps you should try again, copying one file each time, in the right
sequence (I do not recall, which one, but only two files, similarly to
how sys would do it). I did such "manual sys" once on MSDOS 6 (5???)
floppy and it worked (booted).

> Next step will be to try with Norton Disk Doctor.

Watcom C?
DJGPP?

I keep promising myself to do such stuff one day, only with FreeDOS,
plus some utils to refresh my long forgotten i386 assembler. So, it is
probably FASM nowadays. And some editor which is at least minimally
usable... Or some really cheap alternative, with the same under
DOSBOX.

-- 
Regards,
Tomasz Rola

--
** A C programmer asked whether computer had Buddha's nature.  **
** As the answer, master did "rm -rif" on the programmer's home**
** directory. And then the C programmer became enlightened...  **
** **
** Tomasz Rola  mailto:tomasz_r...@bigfoot.com **

Re: Manchester University Joint System in the 1970s

[Chuck Guzis via cctalk]

On 11/17/2017 09:24 AM, Peter Allan via cctalk wrote:
> I was a student at Manchester University from 1974 to 1980. During that
> time I used the University of Manchester Regional Computer Centre (UMRCC)
> computer system. The so-called Joint System consisted of a CDC 7600 with an
> ICL 1906A front end. We used to submit card decks via a Systime (a PDP-11
> clone, I believe) that functioned as a remote job entry service.
> 
> I am trying to find out information about the structure of those card decks
> (mine were used for shopping lists years ago), and in particular, what the
> first card in the deck was that routed the job to the correct computer.

I can't help you with your specific case, other than to mention that
Purdue University for a time used a 6500 front-ended by a couple of IBM
7094s (IIRC, and it's been a long time--could have been 7090s), that
might give you a clue.  The VIM community wasn't large.

>From my own experience with 6000s, the SCOPE 1BJ overlay was heavily
modified by various sites.   I imagine that the corresponding code in
the SCOPE 2.x JS code was similarly tweaked.

--Chuck

Re: Playing with HP2640B

[Christian Corti via cctalk]

On Fri, 17 Nov 2017, David Collins wrote:

Christian do you know the gauge of the wire you used ? And the current?


It was a wire for cutting polystyrene blocks. The current was a fews 
amperes, I think, driven off a bench power supply.


Christian

Re: WTB: HP-85 16k RAM Module and HPIB Floppy Drive

[Paul Berger via cctalk]

I just checked my 9122C I happen to have open and the interval between 
index pulses is 199.66mS  which would be 300 RPM, which is good news for 
me I can now proceed with adapting a more common 1.44 drive to replace 
my broken one.


Paul.


On 2017-11-17 1:04 PM, Eric Schlaepfer via cctalk wrote:

Check your email. How can you tell if it uses a 600 RPM mechanism or not?

On Thu, Nov 16, 2017 at 3:17 AM, Eric Smith  wrote:


Hi Eric,

It's not urgent, but when you have a chance, could you dump the 9122C
ROM(s) and take high resolution photos of the controller board?

Since it does HD, I suspect it probably does not use a 600 RPM mechanism.

Thanks!

Best regards,
Eric


On Nov 15, 2017 17:45, "Eric Schlaepfer via cctalk" 
wrote:


It'd be interesting to find out how well that PRM-85 works. I've laid out
a
board for a rough equivalent but I haven't fabbed it out. It may be
cheaper
for me to buy that instead.

I've also got a 9122C but I don't have the mass storage ROM so I can't use
it with my 85. Right now I'm using it with my 9000 series 300.

On Tue, Nov 14, 2017 at 8:26 PM, Mark J. Blair via cctalk <
cctalk@classiccmp.org> wrote:




On Nov 14, 2017, at 20:11, Ed Sharpe via cctalk <

cctalk@classiccmp.org>

wrote:

wondervifcthec9122 drives,will work on 85?


I think I can guess what you meant to say there... :)

I’ve ordered a PRM-85 (a modern reprogrammable ROM drawer replacement)
which includes the HP-85B version of the Mass Storage ROM, and the

Extended

Mass Storage ROM. Based on what I have read, I think that should let my

A

model use the newer 9122C drive, and other drives using either the

Amigo or

SS-80 protocols.

I’d like to get the 9122C mostly because I have a much easier time

finding

1.44M media than the older double density media. eBay and I don’t talk,

so

that limits my options a bit. If I had easy access to lots of 3.5” DD
media, then I would consider getting one of the more plentiful (?) other
3.5” HPIB floppy drives.

Manchester University Joint System in the 1970s

[Peter Allan via cctalk]

I was a student at Manchester University from 1974 to 1980. During that
time I used the University of Manchester Regional Computer Centre (UMRCC)
computer system. The so-called Joint System consisted of a CDC 7600 with an
ICL 1906A front end. We used to submit card decks via a Systime (a PDP-11
clone, I believe) that functioned as a remote job entry service.

I am trying to find out information about the structure of those card decks
(mine were used for shopping lists years ago), and in particular, what the
first card in the deck was that routed the job to the correct computer.

I have found information about JOB cards for both ICL computers running
George 3 and for the CDC 7600 running SCOPE 2.1 (which is what the
computers ran), but I believe that neither of these gives the full story
about what we used on the Joint System.

Does anyone who used this system, or similar ones in the UK, recall
anything relevant?

If you have suggestions about where else to post this query, I would be
grateful for that too.

Cheers

Peter Allan

Re: WTB: HP-85 16k RAM Module and HPIB Floppy Drive

[Eric Schlaepfer via cctalk]

Check your email. How can you tell if it uses a 600 RPM mechanism or not?

On Thu, Nov 16, 2017 at 3:17 AM, Eric Smith  wrote:

> Hi Eric,
>
> It's not urgent, but when you have a chance, could you dump the 9122C
> ROM(s) and take high resolution photos of the controller board?
>
> Since it does HD, I suspect it probably does not use a 600 RPM mechanism.
>
> Thanks!
>
> Best regards,
> Eric
>
>
> On Nov 15, 2017 17:45, "Eric Schlaepfer via cctalk" 
> wrote:
>
>> It'd be interesting to find out how well that PRM-85 works. I've laid out
>> a
>> board for a rough equivalent but I haven't fabbed it out. It may be
>> cheaper
>> for me to buy that instead.
>>
>> I've also got a 9122C but I don't have the mass storage ROM so I can't use
>> it with my 85. Right now I'm using it with my 9000 series 300.
>>
>> On Tue, Nov 14, 2017 at 8:26 PM, Mark J. Blair via cctalk <
>> cctalk@classiccmp.org> wrote:
>>
>> >
>> >
>> > > On Nov 14, 2017, at 20:11, Ed Sharpe via cctalk <
>> cctalk@classiccmp.org>
>> > wrote:
>> > >
>> > > wondervifcthec9122 drives,will work on 85?
>> > >
>> >
>> > I think I can guess what you meant to say there... :)
>> >
>> > I’ve ordered a PRM-85 (a modern reprogrammable ROM drawer replacement)
>> > which includes the HP-85B version of the Mass Storage ROM, and the
>> Extended
>> > Mass Storage ROM. Based on what I have read, I think that should let my
>> A
>> > model use the newer 9122C drive, and other drives using either the
>> Amigo or
>> > SS-80 protocols.
>> >
>> > I’d like to get the 9122C mostly because I have a much easier time
>> finding
>> > 1.44M media than the older double density media. eBay and I don’t talk,
>> so
>> > that limits my options a bit. If I had easy access to lots of 3.5” DD
>> > media, then I would consider getting one of the more plentiful (?) other
>> > 3.5” HPIB floppy drives.
>> >
>>
>

Re: DR-DOS

[geneb via cctalk]

On Fri, 17 Nov 2017, Liam Proven wrote:


On 17 November 2017 at 16:44, geneb via cctalk  wrote:


Liam, if you need me to I can build a full distro of OpenDOS 7 - I've got a
machine that I can build the original sources on.


Thanks!

For now, I'm trying to avoid building anything. I believe that the
build process is horribly complex -- I can find the link to a
description of the horrors somewhere. Something like 9 different
compilers are apparently used.

If you've got the same MRS disc that Roger sent me, you've got the whole 
build environment already.  You can kick it off with a single command. 
The only caveat is that you need to boot into OpenDOS/DR-DOS in order to 
get enough free lower RAM to run the build process.


g.

--
Proud owner of F-15C 80-0007
http://www.f15sim.com - The only one of its kind.
http://www.diy-cockpits.org/coll - Go Collimated or Go Home.
Some people collect things for a hobby.  Geeks collect hobbies.

ScarletDME - The red hot Data Management Environment
A Multi-Value database for the masses, not the classes.
http://scarlet.deltasoft.com - Get it _today_!

Re: DR-DOS

[Liam Proven via cctalk]

On 17 November 2017 at 16:44, geneb via cctalk  wrote:
>
> Liam, if you need me to I can build a full distro of OpenDOS 7 - I've got a
> machine that I can build the original sources on.

Thanks!

For now, I'm trying to avoid building anything. I believe that the
build process is horribly complex -- I can find the link to a
description of the horrors somewhere. Something like 9 different
compilers are apparently used.

So I hope not to need that, but appreciate the offer!

What I am planning to do is combine the released boot files for PC-DOS
7.1 and DR-DOS 7.01-8, both with FAT32 and LBA support, with the rest
of the released OSes of both, to make something as complete as
possible.

My plan is then to add on top of that a graphical shell -- DOSSHELL
for PC DOS, ViewMax for DR DOS.

And then add some useful shareware/freeware utilities and apps, to
make a complete useful working environment, for example able to boot
off a USB stick for a distraction-free, non-Internet-capable, writing
tool. There seems to be considerable interest in such things these
days, and of course, the problem with apps that provide
distraction-free clean-screen writing/editing environments is that you
can always just switch apps to something else.

I have DESQview and DESQview/X running in a VM, but not on bare metal.
QEMM seems to have problems on 21st century PC hardware, which is
perhaps unsurprising.

On one of my own Lenovo notebooks, I have a bootable partition with PC
DOS 7.01, MS Word 6, WordPerfect 6.2, Norton Utilities and some other
tools. With power management, but not networking or anything. This
works for me, but they can't be distributed; they're licensed tools.

MS Word 5.5 is a free download, though. I was planning to add tools
such as PC Write, PC Outline, As-Easy-As, WordPerfect Editor, a Norton
Commander clone -- stuff that _is_ distributable.

I also need to add a current DOS antivirus, unfortunately. I think
there still are some.

The theory is to produce something functionally rich that runs in a VM
-- because then I know the hardware environment and can configure
things for it. And something much less functionally-rich that can boot
and run off a USB stick on almost any hardware.

DR-DOS should be re-distributable. PC DOS, I fear not, at least not
fully legitimately. But my download diskette image contains nothing
that IBM itself currently does not offer for free unrestricted
download. I'm hoping that the company will tolerate that, at least.

-- 
Liam Proven • Profile: https://about.me/liamproven
Email: lpro...@cix.co.uk • Google Mail/Talk/Plus: lpro...@gmail.com
Twitter/Facebook/Flickr: lproven • Skype/LinkedIn/AIM/Yahoo: liamproven
UK: +44 7939-087884 • ČR/WhatsApp/Telegram/Signal: +420 702 829 053

Re: DR-DOS

[Liam Proven via cctalk]

On 17 November 2017 at 16:12, william degnan  wrote:
> I have a few original Dr dos disks.  Versions 5, 6, 7.  Would these help if
> I am imaged and uploaded to my site?

What I'd suggest is checking what's there first. :-)

I have DR-DOS 6, from VetusWare. There's a copy on WinWorld but it's
some homemade disks, lacking an installer, IIRC.

I have physical media from the early 1990s somewhere!

I have DR-DOS 7.01/02/03/04/05/8.0/8.1 mostly from WinWorld .

I own an original open source release of 7.01, including sources,
direct from Caldera, on CD. This is from before they changed their
mind and back-pedalled.

I have a full boxed copy of PC DOS 7. It was distributed with
Microsoft Virtual PC, which itself is a free download now. So the VM
is out there and freely available.

My VM is built from the free download version, with ViewMax taken from
the download of DR DOS 6.

I have a working VM of PC DOS 7.1 but I'm still working on that. I
don't currently have a bootable USB of it -- making new bootable
volumes is non-trivial. It's not as simple as SYS or FORMAT /S, alas.
Neither works. I don't think it was meant to, TBH. Ditto the later OEM
releases of DR DOS 7.04/05 -- these were only on Disk Manager and
PartitionMagic boot disks, AFAIK. The whole OS was not updated.

-- 
Liam Proven • Profile: https://about.me/liamproven
Email: lpro...@cix.co.uk • Google Mail/Talk/Plus: lpro...@gmail.com
Twitter/Facebook/Flickr: lproven • Skype/LinkedIn/AIM/Yahoo: liamproven
UK: +44 7939-087884 • ČR/WhatsApp/Telegram/Signal: +420 702 829 053

Re: DR-DOS

[geneb via cctalk]

On Fri, 17 Nov 2017, william degnan via cctalk wrote:


I have a few original Dr dos disks.  Versions 5, 6, 7.  Would these help if
I am imaged and uploaded to my site?



Liam, if you need me to I can build a full distro of OpenDOS 7 - I've got 
a machine that I can build the original sources on.


g.

--
Proud owner of F-15C 80-0007
http://www.f15sim.com - The only one of its kind.
http://www.diy-cockpits.org/coll - Go Collimated or Go Home.
Some people collect things for a hobby.  Geeks collect hobbies.

ScarletDME - The red hot Data Management Environment
A Multi-Value database for the masses, not the classes.
http://scarlet.deltasoft.com - Get it _today_!

Re: Cases (display) for beloved ISA cards?

[Anders Nelson via cctalk]

I mounted a core memory plane in a shadowbox from Target and used a large
paperclip cut into sections as the mount hardware. Folded over and
hot-glued one end to the read of the shadowbox backing, placed the memory
plane at the desired height and folded over the other end of the paperclip
section. I also put a piece of heatshrink tubing on the paperclip end that
contacted the memory plane soas not to scratch it.

Pictures: https://photos.app.goo.gl/dzSX21lOC34MaJxm2

=]

--
Anders Nelson

+1 (517) 775-6129

www.erogear.com

On Fri, Nov 17, 2017 at 2:25 AM, CuriousMarc via cctalk <
cctalk@classiccmp.org> wrote:

> I use shadow boxes from Michael's to display my boards. They have many
> kinds
> http://www.michaels.com/-black-shadowbox-studio-decor/
> M10322044.html?dwvar_M10322044_color=Black
> Marc
>
>
>
> On Nov 16, 2017, at 8:04 AM, Ethan via cctalk 
> wrote:
>
> This message has no content.

Re: DR-DOS

[william degnan via cctalk]

I have a few original Dr dos disks.  Versions 5, 6, 7.  Would these help if
I am imaged and uploaded to my site?

Bill Degnan
twitter: billdeg
vintagecomputer.net
On Nov 17, 2017 10:10 AM, "Liam Proven via cctalk" 
wrote:

> Might be more helpful to include downloads!
>
> I'm still working on VMs, but I know have bootable diskette images of
> both. To the best of my knowledge, this is the first time either has
> been made available.
>
> DR-DOS 7.08 is here:
>
> https://www.dropbox.com/s/cz8nrdv7h4sgr6o/drdep7018.zip?dl=0
>
> You'll need the rest of DR-DOS 7.01 to install a complete OS but
> that's widely available.
>
> A bootable PC DOS 7.1 diskette image is here:
>
> https://www.dropbox.com/s/zsujtvp0gs44qcx/PCDOS71.vfd?dl=0
>
> This is a VirtualBox disk image, containing the PC-DOS 7.1 files from
> the IBM ServerGuide Scripting Toolkit, as made available by IBM and
> described here:
>
> http://toogam.com/software/archive/opsys/dos/ibmpcdos/getpcd71.htm
>
> If you get that first, AIUI that gives you a licence to a personal-use
> copy. I have not modified these files in any way except to combine the
> separately-downloadable files and the boot disk image, and to remove
> any non-PC DOS files from the disk image.
>
> Again, the rest of the OS must be taken from a copy of PC DOS 7.01.
> That too is widely available.
>
> Feedback welcomed.
>
> --
> Liam Proven • Profile: https://about.me/liamproven
> Email: lpro...@cix.co.uk • Google Mail/Talk/Plus: lpro...@gmail.com
> Twitter/Facebook/Flickr: lproven • Skype/LinkedIn/AIM/Yahoo: liamproven
> UK: +44 7939-087884 • ČR/WhatsApp/Telegram/Signal: +420 702 829 053
>

Re: DR-DOS

[Liam Proven via cctalk]

It is *not* my day. I don't know how a copy-and-paste of some plain
text magically acquired attachments; that was not intentional. My
apologies.

-- 
Liam Proven • Profile: https://about.me/liamproven
Email: lpro...@cix.co.uk • Google Mail/Talk/Plus: lpro...@gmail.com
Twitter/Facebook/Flickr: lproven • Skype/LinkedIn/AIM/Yahoo: liamproven
UK: +44 7939-087884 • ČR/WhatsApp/Telegram/Signal: +420 702 829 053

Re: DR-DOS

[Liam Proven via cctalk]

Might be more helpful to include downloads!

I'm still working on VMs, but I know have bootable diskette images of
both. To the best of my knowledge, this is the first time either has
been made available.

DR-DOS 7.08 is here:

https://www.dropbox.com/s/cz8nrdv7h4sgr6o/drdep7018.zip?dl=0

You'll need the rest of DR-DOS 7.01 to install a complete OS but
that's widely available.

A bootable PC DOS 7.1 diskette image is here:

https://www.dropbox.com/s/zsujtvp0gs44qcx/PCDOS71.vfd?dl=0

This is a VirtualBox disk image, containing the PC-DOS 7.1 files from
the IBM ServerGuide Scripting Toolkit, as made available by IBM and
described here:

http://toogam.com/software/archive/opsys/dos/ibmpcdos/getpcd71.htm

If you get that first, AIUI that gives you a licence to a personal-use
copy. I have not modified these files in any way except to combine the
separately-downloadable files and the boot disk image, and to remove
any non-PC DOS files from the disk image.

Again, the rest of the OS must be taken from a copy of PC DOS 7.01.
That too is widely available.

Feedback welcomed.

-- 
Liam Proven • Profile: https://about.me/liamproven
Email: lpro...@cix.co.uk • Google Mail/Talk/Plus: lpro...@gmail.com
Twitter/Facebook/Flickr: lproven • Skype/LinkedIn/AIM/Yahoo: liamproven
UK: +44 7939-087884 • ČR/WhatsApp/Telegram/Signal: +420 702 829 053

Re: TI NaturalLink Disks and Docs

[Jason T via cctalk]

On Nov 16, 2017 21:16, "Jason T"  wrote:


I have the original manuals, along with some other Professional
Computer manuals that were already on Bitsavers, free for shipping if
anyone wants them.  They're not light.


Oops, forgot to mention location. I'm in the USA, near Chicago.

DR-DOS

[Liam Proven via cctalk]

I hope this is vintage enough.

I've been playing around some more with my projects to create VMs /
bootable USB keys with PC DOS 7.1 and DR-DOS.

Right now I'm focusing on DR-DOS 7.1 and the DR OpenDOS Enhancement
Project, because that's FOSS and AFAICS it can be redistributed, which
I can't with DR-DOS 7.02/7.03/7.04/7.05 or DR-DOS 8/8.1, which were
commercially licensed.

I found a download of the last build released:

https://archiveos.org/drdos/

First, it's the wrong size. VirtualBox can't mount it. VMware can.

I truncated it to exactly 2880 sectors using the advice from ``jleg094'' here:

https://forums.virtualbox.org/viewtopic.php?f=4=39141

VBox mounts that. But it won't boot, nor in VMware  -- it just
displays 2 dots and freezes.

Embarrassingly late in the troubleshooting process, I've found why.

I didn't think to check what was on the image! Foolish of me.

I mounted it on a pre-booted VM and looked, and it's blank! There's
nothing in the image at all.

So, I mounted the empty image file as a loop device, copied the boot
files in there and then the rest of the files in the distro archive.

And lo, it works! It boots my VM just fine, and it's now running 7.01-08.

All I need to do now is work out how to make the hard disk bootable,
and I'm in business.

The DR-DOS 7 SYS command won't do it, as the files aren't named
IBMBIOS.COM and IBMSYS.COM -- they're DRBIO.SYS and DRSYS.SYS.

I copied them to the expected names. SYS completes but the disk won't boot.

Next step will be to try with Norton Disk Doctor.

Anyway, if anyone wants a bootable diskette image with DR-DOS 7.01-08,
complete with FAT32 support -- apparently it can even boot from it --
let me know.

-- 
Liam Proven • Profile: https://about.me/liamproven
Email: lpro...@cix.co.uk • Google Mail/Talk/Plus: lpro...@gmail.com
Twitter/Facebook/Flickr: lproven • Skype/LinkedIn/AIM/Yahoo: liamproven
UK: +44 7939-087884 • ČR/WhatsApp/Telegram/Signal: +420 702 829 053

RE: Playing with HP2640B

[Rik Bos via cctalk]

I did it by heating the crt to about 50-60 degrees celsius and used a 
putty-knife.
https://www.flickr.com/photos/hp-fix/albums/72157689357633754
The photos are from a Philips P2000M system but I did it the same way with my 
264X terminals and 9845's systems.
It takes about half an hour to heat and separate the screen from the crt .

-Rik

> The screen on my HP2640 had degenerated quite far. It was only a spot in the
> middle, 2 by 4 inch, that still attached the glass to the CRT. I used a thin 
> fish fillet
> knife to dig through the remaining glue.
> 
> Before
> 
> https://scontent-arn2-1.xx.fbcdn.net/v/t1.0-
> 9/23622163_10155696765784985_6518064439030378363_n.jpg?oh=44cbf7f7f
> 00d6e25155c208124e20a38=5AA7349D
> 
> The result after:
> 
> https://scontent-arn2-1.xx.fbcdn.net/v/t1.0-
> 9/23621971_10155696757184985_1959733265676657917_n.jpg?oh=36a20689
> c0fb5a16de7fc4df138a40e0=5A9993B1
> 
> 
> Anyhow, I researched the glue a bit. The glue is, as far as I understand, PVAc
> (PolyVinylAcetate, sometimes also known as PVA). PVAc is not soluble in water.
> It takes quite high temperature to melt it. However PVAc is soluble in many
> esters. I bought some Butylacetate. It dissolves sample bits of glue from 
> HP2640
> quite well and rapidly. Butylacetate has quite high boiling temperature (about
> 120 degrees centigrade) and thus does not evaporate that quickly. So my idea 
> is
> now to test on a 2645 screen or VR201 screen by adding some butylacetate and
> seal with some thin plastic wrap foil and let it dissolve a bit. Then use the 
> fish
> fillet knife again and repeat the process.
> 
> /Mattis

Re: Playing with HP2640B

[Mattis Lind via cctalk]

The screen on my HP2640 had degenerated quite far. It was only a spot in
the middle, 2 by 4 inch, that still attached the glass to the CRT. I used a
thin fish fillet knife to dig through the remaining glue.

Before

https://scontent-arn2-1.xx.fbcdn.net/v/t1.0-9/23622163_10155696765784985_6518064439030378363_n.jpg?oh=44cbf7f7f00d6e25155c208124e20a38=5AA7349D

The result after:

https://scontent-arn2-1.xx.fbcdn.net/v/t1.0-9/23621971_10155696757184985_1959733265676657917_n.jpg?oh=36a20689c0fb5a16de7fc4df138a40e0=5A9993B1


Anyhow, I researched the glue a bit. The glue is, as far as I understand,
PVAc (PolyVinylAcetate, sometimes also known as PVA). PVAc is not soluble
in water. It takes quite high temperature to melt it. However PVAc is
soluble in many esters. I bought some Butylacetate. It dissolves sample
bits of glue from HP2640 quite well and rapidly. Butylacetate has quite
high boiling temperature (about 120 degrees centigrade) and thus does not
evaporate that quickly. So my idea is now to test on a 2645 screen or VR201
screen by adding some butylacetate and seal with some thin plastic wrap
foil and let it dissolve a bit. Then use the fish fillet knife again and
repeat the process.

/Mattis

Re: Playing with HP2640B

[David Collins via cctalk]

Christian do you know the gauge of the wire you used ? And the current?

Maybe I should try that approach again!

David Collins


> On 17 Nov 2017, at 8:09 pm, Christian Corti via cctalk 
>  wrote:
> 
>> On Thu, 16 Nov 2017, CuriousMarc wrote:
>> What did you do for the screen mold? Hot wire method to separate CRT from 
>> implosion window? Put the CRT in a hot water bath? Chip at the glue? Marc
> 
> What we did on one of our 2645 terminals was the hot wire method. We then 
> attached the "implosion" window to the inner of the case.
> 
> BTW is it really an implosion protection? I don't think so because since the 
> 60s, practically all CRTs have a so-called "integral implosion protection" 
> (thick glass on the front and metal band around the edge). I think it is just 
> an anti-glare filter glass. OTOH American CRTs may be completely different in 
> this aspect compared to European ones.
> 
> Christian

Re: Playing with HP2640B

[David Collins via cctalk]

Marc, in addition to Mattis’ forthcoming reply, my recent experience with a 
moldy 2624A was that the hot wire method was very poor. Too hard to get the 
wire in, didn’t melt the ‘glue’ very well, smelly. Gave up when the wire broke. 

What worked best for me was a flat blade screwdriver that was small enough to 
sit sideways in the gap between the front glass and the tube. I sliced sections 
of the glue and picked them out with a hook. I also squirted in a combination 
of RP7 and household cleaner but not sure either did anything other than 
lubricate the surfaces - they may have helped lift the glue a bit. 

My ‘glue’ was like a layer of silicon rubber which hung on for as long as 
possible but I got it all off without any damage. 

I replaced the front glass and held it on with a bead of black silicon rubber 
used for shower glass. I spaced it from the tube with pieces of wire around the 
edges and pulled them out when the silicon dried. 

Worked well for me but keen to hear how Mattis went. 

I didn’t try the hot water soak but it would probably help. 

David Collins


> On 17 Nov 2017, at 6:12 pm, CuriousMarc via cctalk  
> wrote:
> 
> What did you do for the screen mold? Hot wire method to separate CRT from 
> implosion window? Put the CRT in a hot water bath? Chip at the glue?
> Marc
> 
> 
> 
> On Nov 15, 2017, at 11:48 AM, Mattis Lind via cctalk  
> wrote:
> 
> I have been working on a HP 2640B terminal. It was mostly about fixing the
> "screen mold" problem and cleaning up the liquids that had been seeping out
> from the screen down into the bottom.
> 
> The small coaxial wire that connects the 4.9152 MHz clock signal form the
> power supply (never seen a crystal controlled SMPSU before!) to the
> backplane was broken off, but after fixing that the terminal worked fine.
> Just needed some adjustment to the brightness.
> 
> With the correct terminfo installed it worked quite well as a serial
> terminal to a Linux box.
> 
> Then I tried the short 8008 programs that Christian Corti pointed to
> 
> http://computermuseum.informatik.uni-stuttgart.de/dev_en/hp2644/diag.html
> 
> and
> 
> ftp://computermuseum.informatik.uni-stuttgart.de/hp/hp2644
> 
> I tried both a couple of times. The terminal enter the LOADER mode but just
> hangs completely at the end. I tried different baudrates but no difference.
> 
> The selftest STATUS line tell me 40<802 which should indicate that there
> are 4k memory in the terminal. However there should be 5k since there is
> one 4k board and one combined control store and 1 k RAM board. Maybe there
> is a fault in the 1k SRAM? The terminal doesn't complain though.
> 
> Regardless, the programs listed either starts at adress 3 or 36000
> which should then be within the available space.
> 
> The question is, should these program work for the HP2640B as well? It has
> a 8008 but my guess is that the firmware is different from the 2644. What
> is the joint experience regarding this? Has anyone ran these small programs
> above on a HP2640B?
> 
> The HP 2640B firmware consists of four EA 4900 ROM chips which annoyingly
> are not  anything like normal EPROMs. So dumping will need special
> considerations.
> 
> Has anyone dumped the HP 2640B firmware already? I didn't find it on
> bitsavers.
> 
> /Mattis

Re: Playing with HP2640B

[Christian Corti via cctalk]

On Thu, 16 Nov 2017, CuriousMarc wrote:
What did you do for the screen mold? Hot wire method to separate CRT 
from implosion window? Put the CRT in a hot water bath? Chip at the 
glue? Marc


What we did on one of our 2645 terminals was the hot wire method. We then 
attached the "implosion" window to the inner of the case.


BTW is it really an implosion protection? I don't think so because since 
the 60s, practically all CRTs have a so-called "integral implosion 
protection" (thick glass on the front and metal band around the edge). I 
think it is just an anti-glare filter glass. OTOH American CRTs may be 
completely different in this aspect compared to European ones.


Christian