Re: HP 7970E - interest to split?
On 09/30/2017 10:31 PM, Chuck Guzis via cctalk wrote: On 09/30/2017 06:29 PM, Jon Elson wrote: Ahh, but the genius is built into the heads! Note that nobody recorded 800 BPI on 7-track tapes. I think they supported 200 and 556 BPI, only. There were some low-density 9-track tapes, but generally most 9-tk tapes were 800 BPI. Say what? We certainly did a lot of tape at CDC at 800 NRZI on the 607s.657 and 667. Most IBM 729s, but for the very early models could support 800 NRZI. 800 NRZI for 9 track was common only until about 1970; 1600 PE was available on the 2400 series. By 1975, it had pretty much become the 9 track interchange standard. In spite of packing more data on a piece of tape, 1600 PE is actually more reliable than 800, as a dropped bit transition doesn't corrupt data downstream. OK, I never used 7 track tapes, but I thought that they were recorded at lower density than 9 track. Yes, I know about 1600 PE, 3200 PE and 6250 GCR. Jon
Re: HP 7970E - interest to split?
On 09/30/2017 06:29 PM, Jon Elson wrote: > Ahh, but the genius is built into the heads! Note that nobody > recorded 800 BPI on 7-track tapes. I think they supported 200 and 556 > BPI, only. There were some low-density 9-track tapes, but generally > most 9-tk tapes were 800 BPI. Say what? We certainly did a lot of tape at CDC at 800 NRZI on the 607s.657 and 667. Most IBM 729s, but for the very early models could support 800 NRZI. 800 NRZI for 9 track was common only until about 1970; 1600 PE was available on the 2400 series. By 1975, it had pretty much become the 9 track interchange standard. In spite of packing more data on a piece of tape, 1600 PE is actually more reliable than 800, as a dropped bit transition doesn't corrupt data downstream. --Chuck
Re: HP 7970E - interest to split?
On 09/30/2017 12:47 PM, Chuck Guzis via cctalk wrote: What I found a little surprising is that on a 7970 head assembly, the DC resistance of the 9 track coils is about 76 ohms, but on the 7 track side, the resistance measures out to about 27 ohms. Yet, both feed into the same read amplifiers. On the standard 7970 dual-mode drives, the switching between 7 and 9 track, is performed with a JFET on the input. I use small-signal DIP relays. I would have expected a big difference in the signal levels between the two. Ahh, but the genius is built into the heads! Note that nobody recorded 800 BPI on 7-track tapes. I think they supported 200 and 556 BPI, only. There were some low-density 9-track tapes, but generally most 9-tk tapes were 800 BPI. So, this means that a transition spans less longitudinal distance along the tape. So, you get less output from the head for an 800-BPI transition. For 800 BPI, they might make the head poles a bit shorter, but they HAD to make the gap narrower! The gap must be no more than half the length of a bit, or the signal output rapidly drops. I'm guessing the smaller head poles and narrower gap forced them to use more turns of much smaller wire to get the signal back up to what the read amps need. Jon
Re: HP 7970E - interest to split?
> On Sep 30, 2017, at 11:50 AM, Stefan Skoglund via cctalk > wrote: > > fre 2017-09-29 klockan 12:52 -0400 skrev Paul Koning via cctalk: >> ... >> The approach would be somewhat similar to the disk support in SIMH, which >> does already have "RAW" as one of the formats, meaning direct access to a >> real disk. > > RAW disk does that also includes using a zfs/fc/iscsi volume as disk ? > It should considering they appear as sd{a-z} on the host. I would assume yes, for the reason you mentioned. But I haven't tried it. paul
Re: HP 7970E - interest to split?
What I found a little surprising is that on a 7970 head assembly, the DC resistance of the 9 track coils is about 76 ohms, but on the 7 track side, the resistance measures out to about 27 ohms. Yet, both feed into the same read amplifiers. On the standard 7970 dual-mode drives, the switching between 7 and 9 track, is performed with a JFET on the input. I use small-signal DIP relays. I would have expected a big difference in the signal levels between the two. --Chuck
Re: HP 7970E - interest to split?
On 09/30/2017 06:58 AM, Tony Duell via cctalk wrote: One of my tape drives has a set of equal-value resistors connected to each of the read channels, the others ends of the resistors being brought out to a testpoint. You connect a 'scope there and read a skewmaster tape. The idea is that if the read transitions all occur at the same time (no skew) you get a pefect step on the 'scope, if some are later than others you get a staircase. You adjust the heads for the smallest width of the stairs. Yes, this is the classic NRZI skew adjust testpoint. The resistors sum up the read data latches, that are set by seeing a transition of either polarity on a data channel, and reset by a one-shot that is set to about half a character time. You run a skew tape or a tape written with all ones. If you see a square wave, all is good. If you see a slope on the wave, adjust the skew adjust screws on the head mount to make it as straight as possible. Jon
Re: HP 7970E - interest to split?
fre 2017-09-29 klockan 12:52 -0400 skrev Paul Koning via cctalk: > > On Sep 29, 2017, at 12:33 PM, Jon Elson via cctalk > > wrote: > > > > On 09/29/2017 10:56 AM, Henk Gooijen via cctalk wrote: > >> > >> > >> > >> On a related note my plan is to make a USB-based, Pertec-compatible > >> controller for it. Not sure how SimH connects with peripherals so I'm > >> /very/ eager to talk with someone familiar with its workings. I'll also > >> release all the board files and firmware as open-source. Timeline as always > >> is completely unknown, though I do have a now-vested interest in making it > >> work. > > It looks like it only handles tape container files (.TAP files) right now. > But the machinery basically has a tape emulation module (sim_tape.c) which > has a number of functions roughly corresponding to what a tape drive does > (read forward, write tape mark, rewind, etc.). It doesn't look like a > terribly hard task to support a real tape drive as another "container file > format". One question I can think of is how OS-dependent raw SCSI access is. > > The approach would be somewhat similar to the disk support in SIMH, which > does already have "RAW" as one of the formats, meaning direct access to a > real disk. RAW disk does that also includes using a zfs/fc/iscsi volume as disk ? It should considering they appear as sd{a-z} on the host.
Re: HP 7970E - interest to split?
Hi Chuck, How did you program compile if you were missing a semicolon? I'm assuming you're programming in C and not scripting it somehow... Good news on that front! Was it typical to read a record(s) in reverse if an error was encountered? Sounds like that might require buffering the whole record. Easy for us now certainly. =] -- Anders Nelson +1 (517) 775-6129 www.erogear.com On Sat, Sep 30, 2017 at 1:37 AM, Chuck Guzis via cctalk < cctalk@classiccmp.org> wrote: > Hi Anders, > > I found the reason for my SD card problems--a missing semicolon. There > was supposed to be a stall until SDIO transfer complete; instead of a > stall, the next statement was being executed. > > Argh. It's those little things that really trip you up. > > At any rate, I've even got read-reverse working, so I can read a block, > parity check it and retry automatically if there's an error. > > Not too shabby for a $10 MCU board. > > --Chuck > >
Re: HP 7970E - interest to split?
On Sat, Sep 30, 2017 at 6:32 AM, Chuck Guzis via cctalk wrote: > Still a few too many read errors for my taste, so this weekend is going > to be a session with a 'scope and alignment tape. I think I've got a > way to adjust skew--just hook a logic analyzer probe to each channel and > set the LA to trigger on state changes. The HP box I'm using is good > to about 25 nsec. One of my tape drives has a set of equal-value resistors connected to each of the read channels, the others ends of the resistors being brought out to a testpoint. You connect a 'scope there and read a skewmaster tape. The idea is that if the read transitions all occur at the same time (no skew) you get a pefect step on the 'scope, if some are later than others you get a staircase. You adjust the heads for the smallest width of the stairs. -tony
Re: HP 7970E - interest to split?
Hi Anders, I found the reason for my SD card problems--a missing semicolon. There was supposed to be a stall until SDIO transfer complete; instead of a stall, the next statement was being executed. Argh. It's those little things that really trip you up. At any rate, I've even got read-reverse working, so I can read a block, parity check it and retry automatically if there's an error. Not too shabby for a $10 MCU board. --Chuck
Re: HP 7970E - interest to split?
On 09/29/2017 03:01 PM, Al Kossow via cctalk wrote: > > > On 9/29/17 11:35 AM, Chuck Guzis via cctalk wrote: > >> Does the little Kennedy drive have a vacuum takeup reel? > > No, they are tension arm, very similar design to the 7970 > > I wanted to compare the mechanical design of the 9000 to the 7970 > but don't know if I have the time/interest any more. No, that's not what I meant. Some drives put a slight vacuum on the takeup reel hub, so that the tape "sticks" to the hub--no finger hole needed. I've got all the programming done for the drive, including auto retries if there's a parity error. Reading is pretty good for 50+ year old tapes (the ones I'm reading appear to be from the 1976 Viking missions). They look like session transcripts--you can see the command and the response. Still a few too many read errors for my taste, so this weekend is going to be a session with a 'scope and alignment tape. I think I've got a way to adjust skew--just hook a logic analyzer probe to each channel and set the LA to trigger on state changes. The HP box I'm using is good to about 25 nsec. --Chuck
Re: HP 7970E - interest to split?
On 09/29/2017 01:35 PM, Chuck Guzis via cctalk wrote: On 09/29/2017 09:00 AM, Al Kossow via cctalk wrote: On 9/29/17 8:48 AM, Jon Elson via cctalk wrote: I did a few of these on a lathe years ago. It was a couple minutes job per reel. you are also going to have to cut holes near the hub so that you can get a tape started on the takeup reel. Does the little Kennedy drive have a vacuum takeup reel? The 7970 certainly doesn't--no fans in that box at all. I've wondered about applying a low-tack glue dot to the hub of the takeup reel to speed loading. Yes, some drives had some kind of elastomer ring in the takeup reel that would grab most tapes and wrap them quite nicely with no finger hole. Jon
Re: HP 7970E - interest to split?
On 9/29/17 11:35 AM, Chuck Guzis via cctalk wrote: > Does the little Kennedy drive have a vacuum takeup reel? No, they are tension arm, very similar design to the 7970 I wanted to compare the mechanical design of the 9000 to the 7970 but don't know if I have the time/interest any more.
Re: HP 7970E - interest to split?
On 09/29/2017 09:00 AM, Al Kossow via cctalk wrote: > > > On 9/29/17 8:48 AM, Jon Elson via cctalk wrote: > >> I did a few of these on a lathe years ago. It was a couple minutes job per >> reel. > > you are also going to have to cut holes near the hub so that you can get a > tape started > on the takeup reel. Does the little Kennedy drive have a vacuum takeup reel? The 7970 certainly doesn't--no fans in that box at all. I've wondered about applying a low-tack glue dot to the hub of the takeup reel to speed loading. --Chuck
Re: HP 7970E - interest to split?
> On Sep 29, 2017, at 12:33 PM, Jon Elson via cctalk > wrote: > > On 09/29/2017 10:56 AM, Henk Gooijen via cctalk wrote: >> >> >> >> On a related note my plan is to make a USB-based, Pertec-compatible >> controller for it. Not sure how SimH connects with peripherals so I'm >> /very/ eager to talk with someone familiar with its workings. I'll also >> release all the board files and firmware as open-source. Timeline as always >> is completely unknown, though I do have a now-vested interest in making it >> work. It looks like it only handles tape container files (.TAP files) right now. But the machinery basically has a tape emulation module (sim_tape.c) which has a number of functions roughly corresponding to what a tape drive does (read forward, write tape mark, rewind, etc.). It doesn't look like a terribly hard task to support a real tape drive as another "container file format". One question I can think of is how OS-dependent raw SCSI access is. The approach would be somewhat similar to the disk support in SIMH, which does already have "RAW" as one of the formats, meaning direct access to a real disk. > MANY, MANY years ago I got a surplus Pertec key to tape system that had a 7" > 9-track 800 BPI NRZI drive connected to hardwired logic. You could key in > data, verify data by re-keying it, and read back data to a panel of light > bulbs. It had core memory for the data buffer. > > I found the right place to slice the sections apart and have what was pretty > close to the unformatted Pertec interface. > I then wrote a mostly software-driven interface to read and write tape blocks > on my CP/M Z-80 system. I created tapes and took them in to work to map them > and got it to write ASCII text files in VAX ANSI-D format. It really was not > that complicated. This was a read/write drive with only a single data gap. > So, to write and check a record, you had to write it, back up and read it. I > used it for making backups. > > I think you could use a Beagle Bone and the PRU microcontrollers in it to do > a Pertec unformatted interface. I wonder if a BBB is fast enough that you can just drive the Pertec interface directly from the GPIO pins. At 1 GHz lots of things become possible in software... I noticed there is a BB "Cape" (I/O board) with a medium size FPGA on it. Haven't found a use for that yet, but it looks pretty powerful for those case where software isn't quite fast enough. paul
Re: HP 7970E - interest to split?
On 09/29/2017 10:56 AM, Henk Gooijen via cctalk wrote: On a related note my plan is to make a USB-based, Pertec-compatible controller for it. Not sure how SimH connects with peripherals so I'm /very/ eager to talk with someone familiar with its workings. I'll also release all the board files and firmware as open-source. Timeline as always is completely unknown, though I do have a now-vested interest in making it work. MANY, MANY years ago I got a surplus Pertec key to tape system that had a 7" 9-track 800 BPI NRZI drive connected to hardwired logic. You could key in data, verify data by re-keying it, and read back data to a panel of light bulbs. It had core memory for the data buffer. I found the right place to slice the sections apart and have what was pretty close to the unformatted Pertec interface. I then wrote a mostly software-driven interface to read and write tape blocks on my CP/M Z-80 system. I created tapes and took them in to work to map them and got it to write ASCII text files in VAX ANSI-D format. It really was not that complicated. This was a read/write drive with only a single data gap. So, to write and check a record, you had to write it, back up and read it. I used it for making backups. I think you could use a Beagle Bone and the PRU microcontrollers in it to do a Pertec unformatted interface. The only issue is that the PRUs have a fast local memory of very limited size. There is a way to open a memory map to the ARM system memory from the PRU, although the shared memory is 12 K bytes, which might be enough to handle many uses. I did an FPGA-based adapter to Pertec formatted interface using the parallel port. (Slow, but I already had all the FPGA and computer side infrastructure to make that work.) I have some CDC Keystone (92185) drives. Jon
Re: HP 7970E - interest to split?
On 9/29/17 8:48 AM, Jon Elson via cctalk wrote: > I did a few of these on a lathe years ago. It was a couple minutes job per > reel. you are also going to have to cut holes near the hub so that you can get a tape started on the takeup reel.
RE: HP 7970E - interest to split?
Van: Anders Nelson via cctalk<mailto:cctalk@classiccmp.org> Verzonden: vrijdag 29 september 2017 05:57 Aan: General Discussion: On-Topic and Off-Topic Posts<mailto:cctalk@classiccmp.org> Onderwerp: Re: HP 7970E - interest to split? Update: I bought the Kennedy 9800 as it pushed all my buttons at once. Now I'm looking for 8" mag tapes/reels that will fit! Anyone know where I can find these, maybe 3pcs? I could laser-cut some frosted acrylic or machine some frosted polycarbonate I suppose but I'd rather just buy it, plus that would include a dust cover. On a related note my plan is to make a USB-based, Pertec-compatible controller for it. Not sure how SimH connects with peripherals so I'm /very/ eager to talk with someone familiar with its workings. I'll also release all the board files and firmware as open-source. Timeline as always is completely unknown, though I do have a now-vested interest in making it work. Be well! Looking forward to see that controller “materialize”. I could -give- you 3 8” mag tapes with (manual) sealing ring, but the catch is, I am in the Netherlands. Don’t know what shipping cost would be, but my guess is between $25 - $35. If you cannot get the 8” tapes over there, this might be an option. I saw the 9800 auction briefly. Nice looking unit! From memory, the tape reel has the same size as fitting on the TS03? I will measure the reel dimensions tomorrow to make sure that they are 8”. I have open reel tapes in 2 sizes, so probably it is 10.5” and 8”, although ISTR that the size was 7”. Henk
Re: HP 7970E - interest to split?
On 09/28/2017 11:44 PM, Anders Nelson via cctalk wrote: Hi Chuck, Yeah I could try that but unless I can separate the reel halves from the hub I'd have to make a jig of sorts to absorb the laser beam on the bottom side of the cut. Can the sides be separated? And is it possible to cut down a dust cover? I did a few of these on a lathe years ago. It was a couple minutes job per reel. Dust cover? You mean the ring that goes around the reel? Yes, these can be cut down. Generally, they have black plastic parts that snap into a hole on the end of the ring. You take out one of the end pieces, cut the ring and then cut the hole in the ring that the end piece fits into with an X-acto knife. You may have to narrow the rims of the reel so the ring fits right. That's why the lathe is better than the laser cutter. Generally, the flanges are glued together to the hub, and you will not be able to disassemble them. Jon
RE: HP 7970E - interest to split?
Van: Steve Malikoff via cctalk<mailto:cctalk@classiccmp.org> Verzonden: vrijdag 29 september 2017 09:26 Aan: General Discussion: On-Topic and Off-Topic Posts<mailto:cctalk@classiccmp.org> Onderwerp: Re: HP 7970E - interest to split? On my Kennedy 9000s the rubber O-rings have expanded on all the spindles and a reel has a lot of trouble being pushed on and removed. I plan to replace them with neoprene O-rings of the original size. These are readily available and cheap from bearing supplies stores, I'll get a range of close sizes and find the right one. Steve. I have read that putting the rubber rings in warm water will make them shrink to their orginal sze, but keep their Specifications. Worth a try …
Re: HP 7970E - interest to split?
Chuck said: > On 09/28/2017 08:57 PM, Anders Nelson via cctalk wrote: >> Update: I bought the Kennedy 9800 as it pushed all my buttons at once. >> >> Now I'm looking for 8" mag tapes/reels that will fit! Anyone know where I >> can find these, maybe 3pcs? I could laser-cut some frosted acrylic or >> machine some frosted polycarbonate I suppose but I'd rather just buy it, >> plus that would include a dust cover. > > Why not just laser-cut down a 10.5" reel? The hub dimensions are the same. > > --Chuck Or take the reels to a engineering shop and ask them to turn them down on a lathe, it should be a very simple job for them. Besides, there are lots of 10.5" dia tapes available on eBay, and I'm sure I've seen sellers with 8" tape reels. On my Kennedy 9000s the rubber O-rings have expanded on all the spindles and a reel has a lot of trouble being pushed on and removed. I plan to replace them with neoprene O-rings of the original size. These are readily available and cheap from bearing supplies stores, I'll get a range of close sizes and find the right one. Steve.
Re: HP 7970E - interest to split?
Hi Chuck, Yeah I could try that but unless I can separate the reel halves from the hub I'd have to make a jig of sorts to absorb the laser beam on the bottom side of the cut. Can the sides be separated? And is it possible to cut down a dust cover? =] -- Anders Nelson +1 (517) 775-6129 www.erogear.com On Fri, Sep 29, 2017 at 12:12 AM, Chuck Guzis via cctalk < cctalk@classiccmp.org> wrote: > On 09/28/2017 08:57 PM, Anders Nelson via cctalk wrote: > > Update: I bought the Kennedy 9800 as it pushed all my buttons at once. > > > > Now I'm looking for 8" mag tapes/reels that will fit! Anyone know where I > > can find these, maybe 3pcs? I could laser-cut some frosted acrylic or > > machine some frosted polycarbonate I suppose but I'd rather just buy it, > > plus that would include a dust cover. > > Why not just laser-cut down a 10.5" reel? The hub dimensions are the same. > > --Chuck > >
Re: HP 7970E - interest to split?
On 09/28/2017 08:57 PM, Anders Nelson via cctalk wrote: > Update: I bought the Kennedy 9800 as it pushed all my buttons at once. > > Now I'm looking for 8" mag tapes/reels that will fit! Anyone know where I > can find these, maybe 3pcs? I could laser-cut some frosted acrylic or > machine some frosted polycarbonate I suppose but I'd rather just buy it, > plus that would include a dust cover. Why not just laser-cut down a 10.5" reel? The hub dimensions are the same. --Chuck
Re: HP 7970E - interest to split?
Update: I bought the Kennedy 9800 as it pushed all my buttons at once. Now I'm looking for 8" mag tapes/reels that will fit! Anyone know where I can find these, maybe 3pcs? I could laser-cut some frosted acrylic or machine some frosted polycarbonate I suppose but I'd rather just buy it, plus that would include a dust cover. On a related note my plan is to make a USB-based, Pertec-compatible controller for it. Not sure how SimH connects with peripherals so I'm /very/ eager to talk with someone familiar with its workings. I'll also release all the board files and firmware as open-source. Timeline as always is completely unknown, though I do have a now-vested interest in making it work. Be well! On Tue, Sep 26, 2017 at 10:42 PM Anders Nelson wrote: > Well there goes my evening, thanks Chuck! > > -- > Anders Nelson > > +1 (517) 775-6129 > > www.erogear.com > > On Tue, Sep 26, 2017 at 10:09 PM, Chuck Guzis via cctalk < > cctalk@classiccmp.org> wrote: > >> On 09/26/2017 06:45 PM, Anders Nelson via cctalk wrote: >> > Cool, is there documentation available for this formatting and >> > error-check/correction algorithm and structure? I'd like to take a look! >> >> A good place to start is the HP "Introduction to Magnetic Tape" in >> bitsavers: >> >> >> http://bitsavers.informatik.uni-stuttgart.de/pdf/hp/tape/MVD-014_introToMagTap_Apr71.pdf >> >> --Chuck >> >> > -- -- Anders Nelson +1 (517) 775-6129 www.erogear.com
Re: HP 7970E - interest to split?
Well there goes my evening, thanks Chuck! -- Anders Nelson +1 (517) 775-6129 www.erogear.com On Tue, Sep 26, 2017 at 10:09 PM, Chuck Guzis via cctalk < cctalk@classiccmp.org> wrote: > On 09/26/2017 06:45 PM, Anders Nelson via cctalk wrote: > > Cool, is there documentation available for this formatting and > > error-check/correction algorithm and structure? I'd like to take a look! > > A good place to start is the HP "Introduction to Magnetic Tape" in > bitsavers: > > http://bitsavers.informatik.uni-stuttgart.de/pdf/hp/tape/ > MVD-014_introToMagTap_Apr71.pdf > > --Chuck > >
Re: HP 7970E - interest to split?
On 09/26/2017 06:45 PM, Anders Nelson via cctalk wrote: > Cool, is there documentation available for this formatting and > error-check/correction algorithm and structure? I'd like to take a look! A good place to start is the HP "Introduction to Magnetic Tape" in bitsavers: http://bitsavers.informatik.uni-stuttgart.de/pdf/hp/tape/MVD-014_introToMagTap_Apr71.pdf --Chuck
Re: HP 7970E - interest to split?
Cool, is there documentation available for this formatting and error-check/correction algorithm and structure? I'd like to take a look! =] -- Anders Nelson +1 (517) 775-6129 www.erogear.com On Tue, Sep 26, 2017 at 12:26 PM, Chuck Guzis via cctalk < cctalk@classiccmp.org> wrote: > On 09/25/2017 11:40 PM, Steve Malikoff via cctalk wrote: > > > Yes, you will need the controller to at least format, but not sure about > just reading/writing. > > Looking at the interface, it's pretty much a "raw" interface. > > As in a lot of things in life, timing is everything in tapes.Tape > blocks are separated by blank gaps--it's the gap that defines the block > boundaries. In addition, check characters (LRCC in 7 track; CRC+LRCC > in 9 track) are separated from block data by a specified number of bit > times of empty space. > > External logic has to generate/check vertical and horizontal parity, and > insert the required spacing between check characters and inter-block > gaps. In addition, most formatters will correct any single-bit errors > in a block (using the vertical and horizontal parity(LRCC) to locate the > bit in error). > > Logic should also include generation/detection of tapemarks. > > It's not simple, but it's also not rocket science. > > --Chuck > > > >
Re: HP 7970E - interest to split?
On 09/25/2017 11:40 PM, Steve Malikoff via cctalk wrote: > Yes, you will need the controller to at least format, but not sure about just > reading/writing. Looking at the interface, it's pretty much a "raw" interface. As in a lot of things in life, timing is everything in tapes.Tape blocks are separated by blank gaps--it's the gap that defines the block boundaries. In addition, check characters (LRCC in 7 track; CRC+LRCC in 9 track) are separated from block data by a specified number of bit times of empty space. External logic has to generate/check vertical and horizontal parity, and insert the required spacing between check characters and inter-block gaps. In addition, most formatters will correct any single-bit errors in a block (using the vertical and horizontal parity(LRCC) to locate the bit in error). Logic should also include generation/detection of tapemarks. It's not simple, but it's also not rocket science. --Chuck
RE: HP 7970E - interest to split?
> Well, as others have pointed out, a "tape transport" is not the whole > ball-of-wax. You need the ability to format the tape into blocks and then > control tape motion in terms of those blocks. That's what you'd be > responsible for in your added electronics. From the Introduction in the > Kennedy manual:> > "The Model 9800 is equipped with the electronics > necessary for reading and writing tapes and for > controlling the tape motion. The head specifications > and the mechanical and electrical tolerances of the > Model 9800 meet the requirements for IBM compatibility. > > However, the formatting electronics, parity > generator, cyclic redundancy check character (CRCC) > generator, gap control, etc, are not included and > must be provided by the tape control and formatter > in order to generate properly formatted IBM compatible > tapes." Yes, you will need the controller to at least format, but not sure about just reading/writing. Earlier this year I lucked onto a pair of Kennedy 9000 drives from a listmember here in Oz. These are similar in physical size and arrangement to the HP 97970 rather than the more compact 9800 on eBay. Not long after, I found a Kennedy 9219 Format Control Unit formatter in the US which I shipped to Oz. I also acquired an Emulex TC11 unibus controller and an Emulex TC03 Qbus controller but have not been able to find the split ribbon cable yet. However I think this is the standard Pertec interface cable, so I will be posting the boards to this listmember for testing sometime in the near future to find out whether the whole box and dice will actually work together, at least for one of the controllers. I bought some 36-pin edge connectors in anticipation of making up my own split cable based on the listmember's cable. It's going to be a long while before I can report anything, but whatever happens I'll at least be making some notes about it. Steve.
Re: HP 7970E - interest to split?
For generic drives of either 800 or 1600, there were Pertec formatters that drove the three cable Pertec interface (read / write / motion) and was compatible with the P1 P2 parallel formatted interface. The ones I had were one format or another. And they had to be strapped to the speed of the drive. I am not sure if the ones I had which had one or 2 large boards would keep up with faster than 25ips drives. They were about 5" high and mounted under the drive, with an option switch or two on them. I did run them with a second tape unit daisy chained on the parallel formatted side. There was no way to run more than a single 3 cable interface. I've never heard of a way to accomplish that with any controller. The parallel formatted Pertec has unit select, but each drive went to a unique connection. Any drive could be used standalone, as there was no A unit / B type unit at all with the Pertec drives, anyway. thanks Jim On 9/25/2017 11:02 PM, Paul Birkel via cctalk wrote: Well, as others have pointed out, a "tape transport" is not the whole ball-of-wax. You need the ability to format the tape into blocks and then control tape motion in terms of those blocks. That's what you'd be responsible for in your added electronics. From the Introduction in the Kennedy manual: "The Model 9800 is equipped with the electronics necessary for reading and writing tapes and for controlling the tape motion. The head specifications and the mechanical and electrical tolerances of the Model 9800 meet the requirements for IBM compatibility. However, the formatting electronics, parity generator, cyclic redundancy check character (CRCC) generator, gap control, etc, are not included and must be provided by the tape control and formatter in order to generate properly formatted IBM compatible tapes." -Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Anders Nelson via cctalk Sent: Tuesday, September 26, 2017 1:41 AM To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: HP 7970E - interest to split? Ah, yeah that's actually better for my purpose. I'm more concerned with the data interface - can I just read and write bits at will or are there contingencies as someone mentioned before? =] On Tue, Sep 26, 2017 at 12:06 AM Paul Birkel wrote: -Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Anders Nelson via cctalk Sent: Monday, September 25, 2017 7:01 PM To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: HP 7970E - interest to split? Hmmm, interesting. How does the 7970 compare to the Kennedy 9800?: http://www.ebay.com/itm/Kennedy-9800-9-Track-Data-Tape-Subsystem/232493086636 For the same price the Kennedy drive looks more beautimous... =] -- Anders Nelson - http://bitsavers.trailing-edge.com/pdf/kennedy/Kennedy_9800_Digital_Tape_Transport_Operation_and_Maintenance_Manual.pdf 8.5" reels (not the full size 10.5") http://bitsavers.trailing-edge.com/pdf/hp/tape/7970/07970-90885_7970oper_Dec76.pdf - -- -- Anders Nelson +1 (517) 775-6129 www.erogear.com
RE: HP 7970E - interest to split?
Well, as others have pointed out, a "tape transport" is not the whole ball-of-wax. You need the ability to format the tape into blocks and then control tape motion in terms of those blocks. That's what you'd be responsible for in your added electronics. From the Introduction in the Kennedy manual: "The Model 9800 is equipped with the electronics necessary for reading and writing tapes and for controlling the tape motion. The head specifications and the mechanical and electrical tolerances of the Model 9800 meet the requirements for IBM compatibility. However, the formatting electronics, parity generator, cyclic redundancy check character (CRCC) generator, gap control, etc, are not included and must be provided by the tape control and formatter in order to generate properly formatted IBM compatible tapes." -Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Anders Nelson via cctalk Sent: Tuesday, September 26, 2017 1:41 AM To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: HP 7970E - interest to split? Ah, yeah that's actually better for my purpose. I'm more concerned with the data interface - can I just read and write bits at will or are there contingencies as someone mentioned before? =] On Tue, Sep 26, 2017 at 12:06 AM Paul Birkel wrote: > -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Anders > Nelson via cctalk > Sent: Monday, September 25, 2017 7:01 PM > To: General Discussion: On-Topic and Off-Topic Posts > Subject: Re: HP 7970E - interest to split? > > Hmmm, interesting. How does the 7970 compare to the Kennedy 9800?: > > > http://www.ebay.com/itm/Kennedy-9800-9-Track-Data-Tape-Subsystem/232493086636 > > For the same price the Kennedy drive looks more beautimous... > > =] > > -- > Anders Nelson > > - > > > http://bitsavers.trailing-edge.com/pdf/kennedy/Kennedy_9800_Digital_Tape_Transport_Operation_and_Maintenance_Manual.pdf > > 8.5" reels (not the full size 10.5") > > > http://bitsavers.trailing-edge.com/pdf/hp/tape/7970/07970-90885_7970oper_Dec76.pdf > > - > > -- -- Anders Nelson +1 (517) 775-6129 www.erogear.com
Re: HP 7970E - interest to split?
Ah, yeah that's actually better for my purpose. I'm more concerned with the data interface - can I just read and write bits at will or are there contingencies as someone mentioned before? =] On Tue, Sep 26, 2017 at 12:06 AM Paul Birkel wrote: > -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Anders > Nelson via cctalk > Sent: Monday, September 25, 2017 7:01 PM > To: General Discussion: On-Topic and Off-Topic Posts > Subject: Re: HP 7970E - interest to split? > > Hmmm, interesting. How does the 7970 compare to the Kennedy 9800?: > > > http://www.ebay.com/itm/Kennedy-9800-9-Track-Data-Tape-Subsystem/232493086636 > > For the same price the Kennedy drive looks more beautimous... > > =] > > -- > Anders Nelson > > - > > > http://bitsavers.trailing-edge.com/pdf/kennedy/Kennedy_9800_Digital_Tape_Transport_Operation_and_Maintenance_Manual.pdf > > 8.5" reels (not the full size 10.5") > > > http://bitsavers.trailing-edge.com/pdf/hp/tape/7970/07970-90885_7970oper_Dec76.pdf > > - > > -- -- Anders Nelson +1 (517) 775-6129 www.erogear.com
RE: HP 7970E - interest to split?
-Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Anders Nelson via cctalk Sent: Monday, September 25, 2017 7:01 PM To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: HP 7970E - interest to split? Hmmm, interesting. How does the 7970 compare to the Kennedy 9800?: http://www.ebay.com/itm/Kennedy-9800-9-Track-Data-Tape-Subsystem/232493086636 For the same price the Kennedy drive looks more beautimous... =] -- Anders Nelson - http://bitsavers.trailing-edge.com/pdf/kennedy/Kennedy_9800_Digital_Tape_Transport_Operation_and_Maintenance_Manual.pdf 8.5" reels (not the full size 10.5") http://bitsavers.trailing-edge.com/pdf/hp/tape/7970/07970-90885_7970oper_Dec76.pdf -
Re: HP 7970E - interest to split?
Hmmm, interesting. How does the 7970 compare to the Kennedy 9800?: http://www.ebay.com/itm/Kennedy-9800-9-Track-Data-Tape-Subsystem/232493086636 For the same price the Kennedy drive looks more beautimous... =] -- Anders Nelson +1 (517) 775-6129 www.erogear.com On Mon, Sep 25, 2017 at 2:18 PM, Jay West via cctalk wrote: > ED#WROTE > What is really scarce is a 7 track 7970b! > > I have a 7970B (needs some repair) that I would LOVE to trade for a 7970E. > > J > > >
RE: HP 7970E - interest to split?
ED#WROTE What is really scarce is a 7 track 7970b! I have a 7970B (needs some repair) that I would LOVE to trade for a 7970E. J
Re: HP 7970E - interest to split?
What is really scarce is a 7 track 7970b! Had one once... it was the first used HP item I ever sold when I was in the used computer biz early 80s. Wish now I had kept it! Ed# In a message dated 9/25/2017 10:26:10 A.M. US Mountain Standard Time, cctalk@classiccmp.org writes: On 09/25/2017 08:27 AM, Anders Nelson via cctalk wrote: > Cool! Aaa, good to know one of them can't be used individually. > > What might be involved in using one with a PDP-8/e emulated on SimH? I can > build/program any sort of custom USB device to interface this big stuff, > which I'll open-source of course. But does it need special power/startup > stuff beyond a control interface to get it working? I can speak only for my experience with the 7970B, which is an 800 NRZI model and has no "slave' mode. The distinguishing characteristic on the 7970E between master and slave is that the slave does not contain the 1600 PE read or write circuitry. If you're accustomed to a Pertec interface, then the 800 interface isn't terribly different, just dumber. You still have a connector for the basic motion and status commands (i.e. forward, reverse, rewind, high-speed and online, loadpoint, ready, protect) and you have two 8-bit+parity clocked data channels for read and write respectively, each with their own connector. However, there is no formatter, as on Pertec interface drives. You get the raw, framed and deskewed data on read and pretty much anything you want to put in on write. No "handshaking" as the interfaces are not buffered. Thanks to Al, I've just adapted a 7970B to used a combination head stack for 7 and 9 track tapes. Some 7970Es already come so equipped, but they're not common. I fabricated a small PCB with 5 miniature DPDT relays to do the switching and it fits right under the head assembly, with the B's 9-track read amplifier plugging in as usual. The lack of a formatter means that you'll have to do the work of gap detection, parity checking/generation and CRC/LRCC interpretation and generation yourself, as well as manage the control lines. I used a small STM32F407 MCU board (about $10) which has lots of 5V tolerant I/O, so receiving data and status is no problem. For driving control lines, simply set the GPIO pins for open-drain operation. There's something like 24ma of sinking capacity on those, so again, no need for intermediate logic. Since I'm interested in reading tapes, but not writing them, I can't address the issue of what to do about that end. My setup uses a serial port for interaction and a USB port that makes the onboard SDHC look like a generic storage device. So, read a tape, dump the data into the SDHC (Chan's FATFS software is useful); suck it out via the USB port to a PeeSee. To handle 1600 PE data would require yet another layer of software. I realize that not many are interested in my peculiar needs, but perhaps this will go to answer a question or two. --Chuck
Re: HP 7970E - interest to split?
On 09/25/2017 08:27 AM, Anders Nelson via cctalk wrote: > Cool! Aaa, good to know one of them can't be used individually. > > What might be involved in using one with a PDP-8/e emulated on SimH? I can > build/program any sort of custom USB device to interface this big stuff, > which I'll open-source of course. But does it need special power/startup > stuff beyond a control interface to get it working? I can speak only for my experience with the 7970B, which is an 800 NRZI model and has no "slave' mode. The distinguishing characteristic on the 7970E between master and slave is that the slave does not contain the 1600 PE read or write circuitry. If you're accustomed to a Pertec interface, then the 800 interface isn't terribly different, just dumber. You still have a connector for the basic motion and status commands (i.e. forward, reverse, rewind, high-speed and online, loadpoint, ready, protect) and you have two 8-bit+parity clocked data channels for read and write respectively, each with their own connector. However, there is no formatter, as on Pertec interface drives. You get the raw, framed and deskewed data on read and pretty much anything you want to put in on write. No "handshaking" as the interfaces are not buffered. Thanks to Al, I've just adapted a 7970B to used a combination head stack for 7 and 9 track tapes. Some 7970Es already come so equipped, but they're not common. I fabricated a small PCB with 5 miniature DPDT relays to do the switching and it fits right under the head assembly, with the B's 9-track read amplifier plugging in as usual. The lack of a formatter means that you'll have to do the work of gap detection, parity checking/generation and CRC/LRCC interpretation and generation yourself, as well as manage the control lines. I used a small STM32F407 MCU board (about $10) which has lots of 5V tolerant I/O, so receiving data and status is no problem. For driving control lines, simply set the GPIO pins for open-drain operation. There's something like 24ma of sinking capacity on those, so again, no need for intermediate logic. Since I'm interested in reading tapes, but not writing them, I can't address the issue of what to do about that end. My setup uses a serial port for interaction and a USB port that makes the onboard SDHC look like a generic storage device. So, read a tape, dump the data into the SDHC (Chan's FATFS software is useful); suck it out via the USB port to a PeeSee. To handle 1600 PE data would require yet another layer of software. I realize that not many are interested in my peculiar needs, but perhaps this will go to answer a question or two. --Chuck
Re: HP 7970E - interest to split?
That sounds very plausible, Mike. It's too far for me, but I bet somebody local could get both lots for $1000, by picking them up and saving them the hassle of crating etc. -- Robert On Mon, Sep 25, 2017 at 12:07 PM, Mike Loewen via cctalk wrote: > On Mon, 25 Sep 2017, Anders Nelson via cctalk wrote: > >> Hi there, here's an eBay auction for two HP 7970E tape drives that appear >> to function: >> >> >> http://www.ebay.com/itm/VINTAGE-HP-7970e-DUAL-Tape-Drive-Cabinet-Reel-to-Reel-Player-/192204691239 >> >> I'm curious if anyone is looking for one of these drives. I'm not sure if >> I >> want to pull the trigger on something expensive I won't use until I have >> free time, but I imagine stuff like this is only getting more rare. I have >> a Remex paper tape reader in seemingly perfect condition I intend to use >> with an emulated PDP-8/e (using Rod Smallwood's repro front panel), but >> it'd be awesome to be able to save stuff too. > > >I believe these drives were originally attached to the 2117F in this > auction: > > Ebay 401311487499 > >I zoomed in on the first photo and it appears that the upper drive is a > 7970E and the lower is a 7970B. The tape controller board sets in their > 2117F are 13183 (7970E) and 13181 (7970B), which is why I think these two > items belong together. The 7970B was nominally 800bpi NRZI, while the 7970E > was 1600bpi PE. However, each drive had options, so it's impossible to say > what capabilities are there without seeing the option numbers. > >If someone wanted to pick up both items, you'd have a nice setup. > > > Mike Loewen mloe...@cpumagic.scol.pa.us > Old Technology http://q7.neurotica.com/Oldtech/
Re: HP 7970E - interest to split?
On Mon, 25 Sep 2017, Anders Nelson via cctalk wrote: Hi there, here's an eBay auction for two HP 7970E tape drives that appear to function: http://www.ebay.com/itm/VINTAGE-HP-7970e-DUAL-Tape-Drive-Cabinet-Reel-to-Reel-Player-/192204691239 I'm curious if anyone is looking for one of these drives. I'm not sure if I want to pull the trigger on something expensive I won't use until I have free time, but I imagine stuff like this is only getting more rare. I have a Remex paper tape reader in seemingly perfect condition I intend to use with an emulated PDP-8/e (using Rod Smallwood's repro front panel), but it'd be awesome to be able to save stuff too. I believe these drives were originally attached to the 2117F in this auction: Ebay 401311487499 I zoomed in on the first photo and it appears that the upper drive is a 7970E and the lower is a 7970B. The tape controller board sets in their 2117F are 13183 (7970E) and 13181 (7970B), which is why I think these two items belong together. The 7970B was nominally 800bpi NRZI, while the 7970E was 1600bpi PE. However, each drive had options, so it's impossible to say what capabilities are there without seeing the option numbers. If someone wanted to pick up both items, you'd have a nice setup. Mike Loewen mloe...@cpumagic.scol.pa.us Old Technology http://q7.neurotica.com/Oldtech/
Re: HP 7970E - interest to split?
Cool! Aaa, good to know one of them can't be used individually. What might be involved in using one with a PDP-8/e emulated on SimH? I can build/program any sort of custom USB device to interface this big stuff, which I'll open-source of course. But does it need special power/startup stuff beyond a control interface to get it working? =] -- Anders Nelson +1 (517) 775-6129 www.erogear.com On Mon, Sep 25, 2017 at 11:02 AM, Jay West wrote: > I may be convinced to split it with you. I could always use another 7970E. > I can't tell from the pictures if one is master and one is slave only > though.. that would be key. > > > >
RE: HP 7970E - interest to split?
I may be convinced to split it with you. I could always use another 7970E. I can't tell from the pictures if one is master and one is slave only though.. that would be key.
HP 7970E - interest to split?
Hi there, here's an eBay auction for two HP 7970E tape drives that appear to function: http://www.ebay.com/itm/VINTAGE-HP-7970e-DUAL-Tape-Drive-Cabinet-Reel-to-Reel-Player-/192204691239 I'm curious if anyone is looking for one of these drives. I'm not sure if I want to pull the trigger on something expensive I won't use until I have free time, but I imagine stuff like this is only getting more rare. I have a Remex paper tape reader in seemingly perfect condition I intend to use with an emulated PDP-8/e (using Rod Smallwood's repro front panel), but it'd be awesome to be able to save stuff too. I'm in NYC and the drives are in Virginia - anyone around the area interested in splitting the haul? Again I'll have to mull it over but I want one! =] -- Anders Nelson +1 (517) 775-6129 www.erogear.com