On 2015-12-01 19:04, Johnny Billquist wrote:
On 2015-12-01 18:09, Paul Koning wrote:
I suppose it's possible to do something like interleaving where
consecutive sector addresses are not physically adjacent on the
media. Come to think of it, that's exactly what the MSCP RX50
controllers do, si
On 12/01/2015 09:25 AM, Charles Anthony wrote:
This meant that a command to "read sector 4" would return whichever sector
4 passed under the head first. If you did 'read sector 2', 'read sector 4'
you would get the first one; 'read sector 6', 'read sector 4', you would
get the second.
Interleav
On 2015-12-01 18:09, Paul Koning wrote:
On Nov 30, 2015, at 8:39 PM, Johnny Billquist wrote:
On 2015-12-01 02:19, Paul Koning wrote:
On Nov 30, 2015, at 8:12 PM, Johnny Billquist wrote:
...
DECtape never did interleaving that I know of.
Sure it does. The DOS format, which was adopted
I'm remembering correctly, . . .
DIRectory on track 17.
256 bytes per sector.
Each sector within a file has 252 bytes of data and a 4 byte pointer to
the track and sector number of the next sector
GCR (with a different GCR pattern for the 13 sector V 16 sector disks)
It had a sector interleave
On Tue, Dec 1, 2015 at 9:09 AM, Paul Koning wrote:
>
> > On Nov 30, 2015, at 8:39 PM, Johnny Billquist wrote:
> >
> > On 2015-12-01 02:19, Paul Koning wrote:
> >>
> >>> On Nov 30, 2015, at 8:12 PM, Johnny Billquist
> wrote:
> >>>
> >>> ...
> >>> DECtape never did interleaving that I know of.
>
> On Nov 30, 2015, at 8:39 PM, Johnny Billquist wrote:
>
> On 2015-12-01 02:19, Paul Koning wrote:
>>
>>> On Nov 30, 2015, at 8:12 PM, Johnny Billquist wrote:
>>>
>>> ...
>>> DECtape never did interleaving that I know of.
>>
>> Sure it does. The DOS format, which was adopted by RSTS, has 4
>Paul Koning wrote:
The reason for the interleaving on DECtape is the start/stop time. To run
non-interleaved at high speed you have to leave the tape running (no "stop"
commands) and you have to issue the next command quickly. RT-11 could do that; DOS could
not.
When I attempted to evalu
On 2015-12-01 02:19, Paul Koning wrote:
On Nov 30, 2015, at 8:12 PM, Johnny Billquist wrote:
...
DECtape never did interleaving that I know of.
Sure it does. The DOS format, which was adopted by RSTS, has 4 way
interleaving. If you write a 500 block file, it writes every 4th block
forwa
> On Nov 30, 2015, at 8:12 PM, Johnny Billquist wrote:
>
> ...
> DECtape never did interleaving that I know of.
Sure it does. The DOS format, which was adopted by RSTS, has 4 way
interleaving. If you write a 500 block file, it writes every 4th block
forward, then fills in one set of gaps r
Jerry Weiss
j...@ieee.org
> On Nov 30, 2015, at 7:12 PM, Johnny Billquist wrote:
>
> On 2015-12-01 02:06, Jerry Weiss wrote:
>>
>>
>> The TU58 was a block addressable using a cassette tape drive famously(?)
>> called DECtape II. File placement on the two different linear tracks was a
>>
On 2015-12-01 02:06, Jerry Weiss wrote:
On Nov 30, 2015, at 6:35 PM, Paul Koning wrote:
On Nov 30, 2015, at 4:45 PM, Fred Cisin wrote:
Oversimplified remedial tutorial:
Ideally, the system reads a sector, does what it has to do with the content,
and goes back for the next one, and can re
On Nov 30, 2015, at 6:35 PM, Paul Koning wrote:
>
>
>> On Nov 30, 2015, at 4:45 PM, Fred Cisin wrote:
>>
Oversimplified remedial tutorial:
Ideally, the system reads a sector, does what it has to do with the
content, and goes back for the next one, and can read every sector of t
> On Nov 30, 2015, at 4:45 PM, Fred Cisin wrote:
>
>>> Oversimplified remedial tutorial:
>>> Ideally, the system reads a sector, does what it has to do with the
>>> content, and goes back for the next one, and can read every sector of the
>>> track in a single revolution.
>
> From: "Paul Koni
On 11/30/2015 03:17 PM, Charles Anthony wrote:
One of the drum computers had the address of the next instruction as
an operand of the instruction; the programmer would scatter the
instructions according to the execution time of the instructions;
IIRC "assembler" referred to the process of conver
On Mon, Nov 30, 2015 at 3:13 PM, Chuck Guzis wrote:
> On 11/30/2015 02:09 PM, Mike Stein wrote:
>
>> Nothing wrong with what you wrote that I can see; excellent tutorial
>> IMO.
>>
>
> The issue of "floppy interleave" pretty much went away when memory got
> cheap enough to buffer an entire track,
On 11/30/2015 02:09 PM, Mike Stein wrote:
Nothing wrong with what you wrote that I can see; excellent tutorial
IMO.
The issue of "floppy interleave" pretty much went away when memory got
cheap enough to buffer an entire track, provided the controller is
capable of 1:1 interleave transfers.
On Mon, Nov 30, 2015 at 1:45 PM, Fred Cisin wrote:
> Oversimplified remedial tutorial:
>>> Ideally, the system reads a sector, does what it has to do with the
>>> content, and goes back for the next one, and can read every sector of the
>>> track in a single revolution.
>>>
>>
> From: "Paul Koni
Nothing wrong with what you wrote that I can see; excellent tutorial IMO.
m
- Original Message -
From: "Fred Cisin"
To: "General Discussion: On-Topic and Off-Topic Posts"
Sent: Monday, November 30, 2015 4:45 PM
Subject: Re: Sector Interleave
>>> Ove
Oversimplified remedial tutorial:
Ideally, the system reads a sector, does what it has to do with the content,
and goes back for the next one, and can read every sector of the track in a
single revolution.
From: "Paul Koning"
Your writeup was aimed at floppy disks, but interleave may also ap
- Original Message -
From: "Paul Koning"
Sent: Monday, November 30, 2015 3:55 PM
> On Nov 30, 2015, at 3:45 PM, Fred Cisin wrote:
>
> Oversimplified remedial tutorial:
> Ideally, the system reads a sector, does what it has to do with the content,
> and goes back for the next one, and
> On Nov 30, 2015, at 3:45 PM, Fred Cisin wrote:
>
> Oversimplified remedial tutorial:
> Ideally, the system reads a sector, does what it has to do with the content,
> and goes back for the next one, and can read every sector of the track in a
> single revolution.
> ...
> It is USUALLY the sam
On Mon, 30 Nov 2015, dwight wrote:
I wrote an interleave formatter for a friend to use on his H89.
He had an enormous data file that took for ever to read in BASIC.
He couldn't believe it could be made to work so much faster.
Oversimplified remedial tutorial:
Ideally, the system reads a sector,
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