4 Feb
2006
4 Feb
'06
9:58 a.m.
Richard <legalize at xmission.com> wrote:
I believe you are correct based on this picture:
<http://www.lenoxx.com/manuals/CD101/Image74.gif>
this picture is for a normal (Philips) cassette player (or similar)
the particular drive is totally different in that the tape catridge itself
contains a belt that moves the two spools.
Here is a picture of such a tape drive:
http://www.series80.org/Articles/tape-cartridge-lr.gif
The HP2648A uses these cartridges as you can see on page 11-1 of the
HP2648A user's manual (available at:
http://hpmuseum.net/document.php?hwfile=423
Now to repair the capstan you may wish to refer to this page:
http://www.series80.org/Articles/capstan-repair.html
**vp
4 Feb
4 Feb
2:40 p.m.
I'm a little curious--what kind of success might one have reading old (20+
years) HP tapes written on an HP9835? I was asked this recently and I
opined that based on what I'd heard, particularly from the HP calculator
group, that the chances of retrieving error-free data was not all that
good.
Was I accurate? Or are the 98xx tapes an exception?
Cheers,
Chuck
2:22 p.m.
At 02:40 PM 2/4/06 -0800, you wrote:
I'm a little curious--what kind of success might
one have reading old (20+
years) HP tapes written on an HP9835? I was asked this recently and I
opined that based on what I'd heard, particularly from the HP calculator
group, that the chances of retrieving error-free data was not all that
good.
Was I accurate? Or are the 98xx tapes an exception?
Yes. No. They're ALL the same tapes and there are only two
different models of tapes drives (but both are very similar and have the
same drive wheel problem). Chances of reading original tapes at all are
less than 50-50 in my experience. First, fix the tape drive and test it
with a sacrifical tape. Once you KNOW it works*, format a couple of tapes
to store the files on (or better yet, hook up a disk drive and save them on
disks) then try to read your original tape. Read a file then immediately
save it. Repeat until you've saved all the files. Don't play around and try
to run the files, read other files or anything else. The chances that
you'll be able to read a file a second time are SLIM. I once experimented
with 13 or 14 HP tapes (ones that all had good drive bands in them). At
least four of them failed within 2 to 3 reads! A few lasted for about 10 or
12 reads (that's about enough to read all the files on a typical tape).
Only three lasted longer and only one lasted till the end of the first day
and it failed within 3 or 4 days. MANY HP tapes fail to read even once due
to bad drive bands, in fact I'd say most of them have that problem. You can
replace the drive belt with one from a newer tape but it's a PITA and I've
never had much luck with it. But I know others that say that they can
replace them and they work ok so I must be doing something wrong. BUT even
if you overcome the drive belt problem, the tape will almost cetainly shed
the magnetic media and you won't be able to read anything beyond that point
since it sees the media-less tapes as an End-Of-Tape hole. VP's webpage has
some excellant pictures of these problems at
<http://www.series80.org/Articles/capstan-repair.html>.
If anyone gets Gung-Ho and gets properly setup and wants to spend some
time recovering files I have a LOT of original HP tapes with HP software.
*Oh yeah, FYI the tape drives will work even if the capstan isn't exactly
the right size. That is it will write and read tapes formatted in it but it
won't be able to read original HP tapes or tapes written in another
machine. IIRC the capstan has to be +/- .008" for it to read properly. It's
been a long time since I worked on the HP-85 drives and I gave away all my
notes but >IIRC< the correct size for the capstan is 0.421" But I may be
completely wrong about that. I'm sure some of you have experimented with
repairing the drives and you realize that your heat shrink tubing, surgical
tubing or whatever you're using only comes in certain thicknesses so it's
difficult to get the capstan the exact size that you want. But here's a
little secret that I used to use. I would repair the capstan then measure
it's o.d. If it was too small then I'd take the tubing off and wrap the
capstan with thin cellopane tape. Cut the end so that it matches up with
the beginning of the tape and doesn't leave a lump. You can even cut the
beginning and end at an angle to minimize any lump. The tape that I used
was 0.001" thick so each layer was 0.002" thick (2 sides of the capstan
remember). I put on enough layers to exactly make up the difference between
the measured o.d. and the desired o.d. When I was rebuilding drives I kept
the final size to within +/- 0.001" and EVERY drive that I sent out worked
fine. The materials that we're working with aren't entirely consistant and
the results aren't always predictable so if the final o.d. was out by more
than .001" I tore everything off and started over. I also measured the
capstand from several different angles to be sure that it was round. If it
wasn't then I'd start over. Yeah, it was a long tedious process. That's
why I don't do it any more!
Joe
Cheers,
Chuck
3:19 p.m.
I'm a little curious--what kind of success might one have reading old (20+
years) HP tapes written on an HP9835? I was asked this recently and I
opined that based on what I'd heard, particularly from the HP calculator
group, that the chances of retrieving error-free data was not all that
good.
Was I accurate? Or are the 98xx tapes an exception?
Alas fairly low. The tapes for the 98x5 machines are much the same
construction as those for the HP85. The problem is that the belt sticks
to the oxide layer on the tape, and/or the tape sticks together, and you
get major loss of the magnetic coating when you try to read the tape.
Needless to say this makes it unreadable.
-tony
2:38 p.m.
At 11:19 PM 2/4/06 +0000, you wrote:
Tony's right. Two things can happen. First, reading the tape will cause
the media to shed but even worse is that if a tape is used with a gooy
capstan the goo will work it's way into the tape and gets wound up bewteen
the layers of tape on one of the hubs. Then it dries there and the next
time that you unwind the tape to that point the dried goo pulls the media
off the tape. I've also HEARD that some of the tapes also stick together
due to fungus, moisture or other things with the same results. You can
deal with the first problem by absolutely minimizing the tape useage. Read
each file then save it on another tape or drive. DON'T play around with the
drive and tape! As for the second problem I guess you could try
unwinding/rewinding each tape by hand to look for any sticking tape but I
haven't tried it. It seems like it would be pointless since you probably
coudn't do anything about it even if you found a stuck layer.
Also the HP-85 tapes and 98xx tapes are EXACTLY the same and have the
same PN. So are the ones used in the HP protocall analyzers, spectrum
analyzers, 2648 terminals and ALL HP products of that era except for the
big DC-600 type tapes used in the HP 9144, etc. They did use a different
tape in some earlier products but they were VERY different and immediately
recognizable. I have a couple of those drives but I've never seen a tape
for them. It was driven like an audio cassette tape via the hubs.
Joe
I'm a little curious--what kind of success might one have reading old (20+
years) HP tapes written on an HP9835? I was asked this recently and I
opined that based on what I'd heard, particularly from the HP calculator
group, that the chances of retrieving error-free data was not all that
good.
Was I accurate? Or are the 98xx tapes an exception?
Alas fairly low. The tapes for the 98x5 machines are much the same
construction as those for the HP85. The problem is that the belt sticks
to the oxide layer on the tape, and/or the tape sticks together, and you
get major loss of the magnetic coating when you try to read the tape.
Needless to say this makes it unreadable.
5 Feb
5 Feb
10:59 a.m.
big DC-600 type tapes used in the HP 9144, etc. They
did use a different
tape in some earlier products but they were VERY different and immediately
recognizable. I have a couple of those drives but I've never seen a tape
for them. It was driven like an audio cassette tape via the hubs.
If that's the tape I'm thinking of, it's used in the 9830, and I think
also the 982. There was an external tape drive for these machines that I
forget the number of (HP9865???)
The tapes are mechanically compatible with audio compact cassettes, but the
tape is almost certainly different. These drives detect the clear leader
by an optical sensor that reflects off the inside of the cassette shell
where you'd expect the capstan/pinch roller to be, you need to use a
light-coloured cassette. I've got a few Verbatim digital cassettes that
work fine in my 9830.
Interesting thing : That drive is mechanically very similar to the one in
a Racal Thermionic Digideck. Similar enough that some parts will
interchange. And the encoding scheme -- a pulse on one track for a '1', a
pulse on the other track for a '0' and a pulse on both tracks for a
marker (in the case of the HP, it's a byte marker) is the same too. As is
the dact that the thing records 9 bits for each byte, the middle bit is
some kind of marker to distinuish headers from data (the advantage of
making it the middle bit is that you can read it with the tape moving in
either direction.
I would guess that the mechanism is not wholely an HP design/build...
-tony
2:45 p.m.
On 2/5/2006 at 6:59 PM ard at p850ug1.demon.co.uk wrote:
If that's the tape I'm thinking of, it's
used in the 9830, and I think
also the 982. There was an external tape drive for these machines that I
forget the number of (HP9865???)
No--the DC-300 is a big tape, thinner, but almost the size of a VHS
cassette. DC-300, DC-600, DC-6150, DC-6250 and several other formats share
the same mechanical layout and size.
I've still got a bunch of the little DC-1000's squirreled away. The drive
(Iwin) has 3.5" FH form factor. Are there any other 3.5" DC-xxx drives?
Anyone remember a really silly format brought out about 1993? Used a 2.5mm
tape in a cart about the size of an audio microcassette. The mechanism was
a Sony helical-scan setup. It could run on 4 AA cells and interfaced
through the parallel port. I was sent one as an evaluation unit and never
could get it to work reliably. Tapes were expensive--about $15--and
available only via Fedex from the manufacturer.
I normally don't send many eval units back, but when I got wind that the
manufacturer was telling customers that that we "were working on a driver"
for it, I sent the unit back with an angry letter. One of my customers
bought 50 of the units anyway and, for all I know, they're still sitting in
a warehouse somewhere, unopened and unused.
Cheers,
Chuck
4:07 p.m.
On 2/5/2006 at 6:59 PM ard at p850ug1.demon.co.uk wrote:
I know what a DC300 looks like. I have a Sidewinder drive on my PERQ....
Joe mentioned that this other HP tape was driven by the hubs like an
audio cassette. A DC300 isn't, it's got the belt-between-the-spools
drive. I rather misinterpretted Joe and thought he said it _was_ like an
audio cassette (which the 9830 tape certainly is).
-tony
If that's the tape I'm thinking of,
it's used in the 9830, and I think
also the 982. There was an external tape drive for these machines that I
forget the number of (HP9865???)
No--the DC-300 is a big tape, thinner, but almost the size of a VHS
cassette. DC-300, DC-600, DC-6150, DC-6250 and several other formats share
the same mechanical layout and size.
4:16 p.m.
On 2/6/2006 at 12:07 AM ard at p850ug1.demon.co.uk wrote:
Joe mentioned that this other HP tape was driven by the
hubs like an
audio cassette. A DC300 isn't, it's got the belt-between-the-spools
drive. I rather misinterpretted Joe and thought he said it _was_ like an
audio cassette (which the 9830 tape certainly is).
Maybe a DC-100?
Cheers,
Chuck
6 Feb
6 Feb
7:47 a.m.
At 06:59 PM 2/5/06 +0000, Tony wrote:
No, the drives and tapes used on the 9830, 9865, and the other 98x0
machines is an earlier tape and it's different. They're more like audio
tapes and have an all plastic shell and the tape is driven via the hubs.
The tapes that I was talking about are similar to the HP-85 tapes but much
larger (DC-600 size) and use an aluminium base plate and are used in the HP
9142, 9144 and 7942 and similar drives. FWIW some of these larger tapes are
marked 16 track and others are 32 track but they both look alike.
big DC-600
type tapes used in the HP 9144, etc. They did use a different
tape in some earlier products but they were VERY different and immediately
recognizable. I have a couple of those drives but I've never seen a tape
for them. It was driven like an audio cassette tape via the hubs.
If that's the tape I'm thinking of, it's used in the 9830, and I think
also the 982. There was an external tape drive for these machines that I
forget the number of (HP9865???)
The tapes are mechanically compatible with audio compact cassettes, but the
tape is almost certainly different. These drives detect the clear leader
by an optical sensor that reflects off the inside of the cassette shell
where you'd expect the capstan/pinch roller to be, you need to use a
light-coloured cassette. I've got a few Verbatim digital cassettes that
work fine in my 9830.
That's good to know. I have a 9830 and a 9865 but I've never tried to
use the tape drives in them.
Interesting thing : That drive is mechanically very similar to the one in
a Racal Thermionic Digideck. Similar enough that some parts will
interchange. And the encoding scheme -- a pulse on one track for a '1', a
pulse on the other track for a '0' and a pulse on both tracks for a
marker (in the case of the HP, it's a byte marker) is the same too. As is
the dact that the thing records 9 bits for each byte, the middle bit is
some kind of marker to distinuish headers from data (the advantage of
making it the middle bit is that you can read it with the tape moving in
either direction.
I would guess that the mechanism is not wholely an HP design/build...
Probably not. I don't really know anything about those older drives but
I know that the HP Journal said that the later drives (HP-85 style) was a
joint program bewteen HP and 3M so I'm assuming that onr or the other (or
both of them) designed it.
Joe
-tony
1:32 p.m.
I picked up a 2nd 2648A in Boise, ID and the capstans look intact on
this one (looking into the case from the tape slot). This gives me
one crappy unit for spares and one good condition unit for play :-).
Now what's a good way to clean the stateful switches on the top of the
keyboard? One of the keyboards has switches that don't release
without a little manual assistance. I figure gunk has gotten into the
switch mechanism over time. I'm *not* going to put this guy through
the dishwasher, I'm too scared of what might happen ;-).
Also, some people were saying that they had a keyboard "without the
tape controls on top", but everything I can see in the 2648A manuals
shows that all the keyboards have the tape controls, but your keyboard
might not have the key overlay. Can someone show me a picture of the
keyboard *without* the tape controls for comparison and get a part
number off it?
--
"The Direct3D Graphics Pipeline"-- code samples, sample chapter, FAQ:
<http://www.xmission.com/~legalize/book/>
Pilgrimage: Utah's annual demoparty
<http://pilgrimage.scene.org>
4:22 p.m.
At 06:59 PM 2/5/06 +0000, Tony wrote:
No, the drives and tapes used on the 9830, 9865, and the other 98x0
machines is an earlier tape and it's different. They're more like audio
tapes and have an all plastic shell and the tape is driven via the hubs.
The tapes that I was talking about are similar to the HP-85 tapes but much
larger (DC-600 size) and use an aluminium base plate and are used in the HP
I nkonw tham... But you said (in a bit you quoted above)
'It was driven like an audio cassette tape via the hubs.'
That applies to the 9820, not to the DC600s...
big
DC-600 type tapes used in the HP 9144, etc. They did use a different
tape in some earlier products but they were VERY different and immediately
recognizable. I have a couple of those drives but I've never seen a tape
for them. It was driven like an audio cassette tape via the hubs.
If that's the tape I'm thinking of, it's used in the 9830, and I think
also the 982. There was an external tape drive for these machines that I
forget the number of (HP9865???) 9142, 9144 and 7942 and similar drives. FWIW some of
these larger tapes are
marked 16 track and others are 32 track but they both look alike.
The tapes for the 9144 and 9145 are pre-formatted by the factory, it's a
special HP format. IIRC the 9145 (32 track) can read but not write the
9144 (16 track) tapes. I only have 9144s.
The 9142 uses plain DC600 tapes. They are not factory-formatted, and
AFAIK the format is one of the QIC standards (QIC24?).
The tapes are mechanically compatible with audio compact cassettes, but the
tape is almost certainly different. These drives detect the clear leader
by an optical sensor that reflects off the inside of the cassette shell
where you'd expect the capstan/pinch roller to be, you need to use a
light-coloured cassette. I've got a few Verbatim digital cassettes that
work fine in my 9830.
That's good to know. I have a 9830 and a 9865 but I've never tried to
use the tape drives in them. from the rear PCB. These plugs are marked
'Motor', 'Solenoid' (also
carries the cassette-in and write-protect
swtich signals), 'Photo' (EOT
sensor) and 'Head' (to Head PCB).
Undo the 3 screws holding the PCB to the bracket, evenly. The spacers and
screws normally stay with the bracket. Remove the PCB.
Undo the long through-bolt holding the front panel in place. Remove the
nut, shakeproof washer, flat washer and spacer. Pull out the bolt (with
spacer, flat washer and shakeproof washer at the head end). Remove the
front panel and slide out the window (it often falls out!). Undo the nut
and bolt holding the earth wire to the front panel, and remove the panel
completely.
Undo the 4 screws holding the motor rear support bracket to the side
frames. Remove the central screw and the bracket. Slide out the motor
assembly from the pivot post.
Disconnect the 4 wires at the back of the head (push-on terminals),
noting their positions. Undo the 2 screws holding the head PCB to the
head plate assembly, Remove the PCB and the spacers.
Undo the 3 screws holding the left side plate to the head plate assmebly.
Remove the plate (unhook the cassette holding spring from inside the side
frame of the head plate). Remove the 2 spacers from the pivot posts.
Turn the drive over, free the right side plate (and complete head plate
assembly) from the posts on the right hand side. Remove the spacers.
To repair the optical EOT sensor, remove the 2 remaining screws on the
PCB (one was removeed when the head PCB was removed). Free the P-clip.
Remove the tape guide from the front of the sensor, and carefully remove
the PCB. It contains an LDR and light bulb.
Back on the main chassis, remove the screw holding the motor pivot post
in place. Remove the post.
Remove the leaf spring from the back of each cassette spindle pulley (one
screw each). Remove the circlip from the front of the cassette spindle,
slide off the plastic washer, then remove the spindle. Remove the second
plastic washer from the face of the pulley. Remove the O-ring from the pulley
Undo the 2 screws holding the brake plate in place. Free the spring, then
lift off the brake plate and the 2 plastic spacers. Note that both of
these must be fitted the right way up.
---------------
-tony
4 Feb
4 Feb
8:45 p.m.
In article <m1F5WhB-000IyFC at p850ug1>,
ard at p850ug1.demon.co.uk (Tony Duell) writes:
Anyone tried readtapes.com with one?
--
"The Direct3D Graphics Pipeline"-- code samples, sample chapter, FAQ:
<http://www.xmission.com/~legalize/book/>
Pilgrimage: Utah's annual demoparty
<http://pilgrimage.scene.org>
I'm a little curious--what kind of success might one have reading old (20+
years) HP tapes written on an HP9835? I was asked this recently and I
opined that based on what I'd heard, particularly from the HP calculator
group, that the chances of retrieving error-free data was not all that
good.
Was I accurate? Or are the 98xx tapes an exception?
Alas fairly low. The tapes for the 98x5 machines are much the same
construction as those for the HP85. The problem is that the belt sticks
to the oxide layer on the tape, and/or the tape sticks together, and you
get major loss of the magnetic coating when you try to read the tape.
Needless to say this makes it unreadable. 
11:11 p.m.
Tony Duell wrote:
Is that specific to the HP tapes, or are all the similar tapes just as
bad? And is there a way to prevent this, like maybe taking it apart and
removing the belt first?
Gordon.
I'm a
little curious--what kind of success might one have reading old (20+
years) HP tapes written on an HP9835? I was asked this recently and I
opined that based on what I'd heard, particularly from the HP calculator
group, that the chances of retrieving error-free data was not all that
good.
Was I accurate? Or are the 98xx tapes an exception?
Alas fairly low. The tapes for the 98x5 machines are much the same
construction as those for the HP85. The problem is that the belt sticks
to the oxide layer on the tape, and/or the tape sticks together, and you
get major loss of the magnetic coating when you try to read the tape.
Needless to say this makes it unreadable.
6 Feb
6 Feb
2 a.m.
At 07:11 AM 2/5/06 +0000, you wrote:
Tony Duell wrote:
Is that specific to the HP tapes, or are all the similar tapes just as
bad? And is there a way to prevent this, like maybe taking it apart and
removing the belt first?
I don't know of any way to prevent it. The case of NIB HP tapes that I
had had been stored inside in an airconditioned building on an Air Force
base so storage conditions don't seem to be a factor. Other brands of
compatible tapes such as the DEC CompacTape (or whatever they call it) and
the PC 40 Mb tapes seem to have the same problems but not as often. But I
think they're all going to deteriorate soon. I THINK the DEC and PC may be
a bit newer. The HP Journal that talked about these tape drives said that
the tapes and drives were developed by 3M and HP. So I believe HP was the
first to use them so the HP tapes are probably the oldest out there.
I don't know what good taking the belt off would do.
I urge everyone to gather their tapes up and try to have someone read
them and store the contents to disk or some other media.
Joe
I'm a
little curious--what kind of success might one have reading old (20+
years) HP tapes written on an HP9835? I was asked this recently and I
opined that based on what I'd heard, particularly from the HP calculator
group, that the chances of retrieving error-free data was not all that
good.
Was I accurate? Or are the 98xx tapes an exception?
Alas fairly low. The tapes for the 98x5 machines are much the same
construction as those for the HP85. The problem is that the belt sticks
to the oxide layer on the tape, and/or the tape sticks together, and you
get major loss of the magnetic coating when you try to read the tape.
Needless to say this makes it unreadable.
Gordon.
8:40 a.m.
In article <3.0.6.16.20060206100054.32e7d0d8 at pop-server.cfl.rr.com>,
"Joe R." <rigdonj at cfl.rr.com> writes:
I urge everyone to gather their tapes up and try to
have someone read
them and store the contents to disk or some other media.
I can understand that important stuff may be out there for HP-85s,
since they are actual computers. The 2648A is a terminal though. A
very sophisticated terminal, but just a terminal. Its my impression
that the tapes would have been used for storing entered data or plot
data as the terminal has an "autoplot" feature (very cool, I only
learned about this last night and didn't know it back in 78 :-).
Was there ever any "software" made for the 2648A? I don't see
anything in the service, reference or user's manual for it. (A big
thanks to hpmuseum.net for having all that stuff scanned!)
--
"The Direct3D Graphics Pipeline"-- code samples, sample chapter, FAQ:
<http://www.xmission.com/~legalize/book/>
Pilgrimage: Utah's annual demoparty
<http://pilgrimage.scene.org>
7:15 a.m.
At 09:40 AM 2/6/06 -0700, Richard wrote:
In article <3.0.6.16.20060206100054.32e7d0d8 at pop-server.cfl.rr.com>,
"Joe R." <rigdonj at cfl.rr.com> writes:
I don't know but it wouldn't surprise me if there was. But there are
lots of other systems that use the same drives and tapes such as the HP
9845, 9835, 9825 calculator/computers along with LOTs of their test equipment.
Joe
I don't see
I urge everyone to gather their tapes up and
try to have someone read
them and store the contents to disk or some other media.
I can understand that important stuff may be out there for HP-85s,
since they are actual computers. The 2648A is a terminal though. A
very sophisticated terminal, but just a terminal. Its my impression
that the tapes would have been used for storing entered data or plot
data as the terminal has an "autoplot" feature (very cool, I only
learned about this last night and didn't know it back in 78 :-).
Was there ever any "software" made for the 2648A? anything in the service, reference or user's manual
for it. (A big
thanks to hpmuseum.net for having all that stuff scanned!)
--
"The Direct3D Graphics Pipeline"-- code samples, sample chapter, FAQ:
<http://www.xmission.com/~legalize/book/>
Pilgrimage: Utah's annual demoparty
<http://pilgrimage.scene.org>
3:13 p.m.
Joe R. wrote:
At 09:40 AM 2/6/06 -0700, Richard wrote:
At least internally there was a basic interpreter for the 2648A (the
graphics terminal, right?)
that ran from the tape drive. Don't know if it was sold as a product...
Bill
Was there ever any "software" made for
the 2648A?
I don't know but it wouldn't surprise me if there was. But there are
lots of other systems that use the same drives and tapes such as the HP
9845, 9835, 9825 calculator/computers along with LOTs of their test equipment.
Joe
7 Feb
7 Feb
12:08 a.m.
In article <43E7D828.2080104 at mcdermith.net>,
Bill McDermith <bill_mcdermith at mcdermith.net> writes:
At least internally there was a basic interpreter for
the 2648A (the
graphics terminal, right?)
Right, the graphics "terminal" -- its really more like a PC, but
externally it looks like a terminal. Inside is a card cage,
processor, memory, tape controller, etc.
that ran from the tape drive. Don't know if it was
sold as a product...
This would be the first I've heard of that; sounds like an internal
hack and not a product as I can't find any mention of software
products for the 2648A anywhere in web sites or HP docs. I don't
suppose you have a tape? :-).
--
"The Direct3D Graphics Pipeline"-- code samples, sample chapter, FAQ:
<http://www.xmission.com/~legalize/book/>
Pilgrimage: Utah's annual demoparty
<http://pilgrimage.scene.org>
1:48 p.m.
On 2/7/06, Richard <legalize at xmission.com> wrote:
This would be the first I've heard of that; sounds like an internal
hack and not a product as I can't find any mention of software
products for the 2648A anywhere in web sites or HP docs. I don't
suppose you have a tape? :-).
I don't know whether basic interpreters exist for other 264x
terminals, but there was a basic interpreter for the 2647F terminal.
The 2647F used externally connected floppy drives instead of tape
drives. I have a 2647F but unfortunately don't have a copy of the
basic disks. Someone on the list (Eric?) mentioned having copies a
long time ago and I didn't follow up and get copies at the time.
Maybe one of the primary uses of 264x tape storage was for HP 1000
storage media. One of the standard boot proms for the HP 1000 will
boot from 264x tape media. I have a set of HP 1000 diagnostic
programs on 264x tape media. Unfortunately they are almost all
unreadable.
4:14 p.m.
In article <1e1fc3e90602071348h508dbd61ide07338198a2c047 at mail.gmail.com>,
Glen Slick <glen.slick at gmail.com> writes:
Maybe one of the primary uses of 264x tape storage was
for HP 1000
storage media. One of the standard boot proms for the HP 1000 will
boot from 264x tape media. I have a set of HP 1000 diagnostic
programs on 264x tape media. Unfortunately they are almost all
unreadable.
Unreadable as in the media is physically damaged or unreadable as in
the physical shape is OK but putting it through the drive doesn't
yield anything useful?
It wouldn't be the first time I've seen someone use a different read
head with older tapes that were "unreadable" and squeeze out the bits
with modern signal processing equipment and an analog signal from a
compatible head.
--
"The Direct3D Graphics Pipeline"-- code samples, sample chapter, FAQ:
<http://www.xmission.com/~legalize/book/>
Pilgrimage: Utah's annual demoparty
<http://pilgrimage.scene.org>
7 p.m.
At 06:14 PM 2/7/2006, Richard wrote:
It wouldn't be the first time I've seen someone
use a different read
head with older tapes that were "unreadable" and squeeze out the bits
with modern signal processing equipment and an analog signal from a
compatible head.
I look forward to the future universal head-head that'll be used
to recover signals from tapes of all types. Do it all in software
and it doesn't need to be real-time.
Is there something physically impossible in this problem that
I'm missing? Certainly old perpendicular N-track head is easy,
and a helical scan flying head is tiny and fast, but aren't
there many possible ways to skin this cat?
- John
8 Feb
8 Feb
10:50 a.m.
On 2/7/06, Richard <legalize at xmission.com> wrote:
Unreadable as in the media is physically damaged or
unreadable as in
the physical shape is OK but putting it through the drive doesn't
yield anything useful?
Unreadable as in the common problem with this type of media where the
oxide has been shedded from the tape in a few spots.
I'm not sure how many tapes there are where I know this has happened.
I might have just not bothered looking at the other tapes and assumed
they would all have the same problem.
Maybe I'll look into the 'baking" suggestions and see if that helps
with some of the tapes that have not yet been damaged.
12:32 p.m.
In article <1e1fc3e90602081050y7696c1a8v36f494004a6a5d3a at mail.gmail.com>,
Glen Slick <glen.slick at gmail.com> writes:
Maybe I'll look into the 'baking"
suggestions and see if that helps
with some of the tapes that have not yet been damaged.
The readtapes.com web site had a page describing how they coped with
shedding media. However, that web site appears to be dead now :-(.
Anyone know the story with readtapes.com?
--
"The Direct3D Graphics Pipeline"-- code samples, sample chapter, FAQ:
<http://www.xmission.com/~legalize/book/>
Pilgrimage: Utah's annual demoparty
<http://pilgrimage.scene.org>
10 Feb
10 Feb
12:49 p.m.
On Tue, 7 Feb 2006, Glen Slick wrote:
I don't know whether basic interpreters exist for
other 264x
terminals, but there was a basic interpreter for the 2647F terminal.
The 2647F used externally connected floppy drives instead of tape
drives. I have a 2647F but unfortunately don't have a copy of the
basic disks. Someone on the list (Eric?) mentioned having copies a
long time ago and I didn't follow up and get copies at the time.
Something about Autoplot triggered a distant memory, and I found a
couple of 5-1/4" diskettes which may be for the 2647F. The first is
labeled AUTOPLOT/47, with a part number of 02647-13401. If I'm reading
the hex dump of what appears to be the directory sector correctly, it has
the following files:
WELCOME
SLIDEX
PIE
AGLX
AUTO
AUTO2
AUTOX
AUTOX2
CTUL001
BASIC
LINEAR
BAR
SLIDE
BACKUP
MESSAGE1
There are two other diskettes, with DEMO/47 and something else I'll
have to check on when I get home.
What filesystem format did the 2647F use?
Mike Loewen mloewen at cpumagic.scol.pa.us
Old Technology http://ripsaw.cac.psu.edu/~mloewen/Oldtech/
13 Feb
13 Feb
1:10 p.m.
On 2/10/06, Mike Loewen <mloewen at cpumagic.scol.pa.us> wrote:
Something about Autoplot triggered a distant memory, and I found a
couple of 5-1/4" diskettes which may be for the 2647F. The first is
labeled AUTOPLOT/47, with a part number of 02647-13401.
There are two other diskettes, with DEMO/47 and
something else I'll
have to check on when I get home.
What filesystem format did the 2647F use?
I have no idea what filesystem format was used on the 2647F. I'll
have to hook mine up and create some data files and then take a look
at the disks. Maybe it is something like LIF.
If you can create some disk images of the disks you have I'd like to
try creating disks from them and see if I do anything interesting with
them. I have just a skimpy user manual for the 2647F but I think it
does have some mention of Autoplot. I'll have to take a look at the
manual.
9 p.m.
On 2/10/06, Mike Loewen <mloewen at cpumagic.scol.pa.us> wrote:
Something about Autoplot triggered a distant memory, and I found a
couple of 5-1/4" diskettes which may be for the 2647F. The first is
labeled AUTOPLOT/47, with a part number of 02647-13401. If I'm reading
the hex dump of what appears to be the directory sector correctly, it has
the following files:
Can you create a disk image of the 02647-13401 disk (and other 2647
disks you may have)? The "getting started with your 2647F" manual
(02647-90036) I have says that disk 02647-13401 is the BASIC /
AUTOPLOT / 47 disk that I am missing.
According to the manual the disks should be formatted with 256 byte
sectors, double sided, 16 sectors per track, 1056 sectors total, which
must mean 33 tracks, although the 13272 Flexible Disc System manual
(13255-91223) says there are 35 tracks.
14 Feb
14 Feb
5:21 a.m.
On Mon, 13 Feb 2006, Glen Slick wrote:
Can you create a disk image of the 02647-13401 disk
(and other 2647
disks you may have)? The "getting started with your 2647F" manual
(02647-90036) I have says that disk 02647-13401 is the BASIC /
AUTOPLOT / 47 disk that I am missing.
I'll make images of the three disks that I have, and send you a pointer
to them.
Mike Loewen mloewen at cpumagic.scol.pa.us
Old Technology http://ripsaw.cac.psu.edu/~mloewen/Oldtech/
15 Feb
15 Feb
11 a.m.
On 6 Feb 2006 at 16:13, Bill McDermith wrote:
At least internally there was a basic interpreter for
the 2648A (the
graphics terminal, right?) that ran from the tape drive. Don't know if
it was sold as a product...
HP sold a 2647A terminal (I have one) with dual DC-100 drives that came
with a BASIC interpreter on mini-cartridge. The tape label says:
Hewlett-Packard Multiplot/BASIC Interpreter
02647-13301 Rev. F 2114-42
-- Dave
11:57 a.m.
Based on posts here and information at hpmuseum.net, it seems that the
2647A and 2649A had a programmable aspect to the equipment, while the
other 264x terminals did not.
hpmuseum.net describes the following models in this line:
2640A introduced 1975, base terminal
2644A introduced 1975, added two mini cartridge tape drives
2645A introduced 1976, replaced the 2644A, "most common"
2648A introduced 1977, added graphics capability
2649A introduced 1977, programmable w/out tape drives
2647A introduced 1978, BASIC programmable w/tape drives & graphics
--
"The Direct3D Graphics Pipeline"-- code samples, sample chapter, FAQ:
<http://www.xmission.com/~legalize/book/>
Pilgrimage: Utah's annual demoparty
<http://pilgrimage.scene.org>
16 Feb
16 Feb
1:31 a.m.
On Wed, 15 Feb 2006, Richard wrote:
Based on posts here and information at hpmuseum.net,
it seems that the
2647A and 2649A had a programmable aspect to the equipment, while the
other 264x terminals did not.
Each 264x terminal is programmable. You can write your own machine code
and load it either from remote or from the tape drive into memory and
execute it. There are several games for these terminals that run on the
builtin processor, for both the i8008 (e.g. HP2644) and the i8080 (e.g.
HP2645/48).
The system calls are well documented in the technical manuals, as well as
all ROM entry points, variables etc. I have about four or five *thick*
binders for the HP2648 with detailed technical descriptions, microcode
listings and schematics for all options that were available.
Christian
6 Feb
6 Feb
4:13 p.m.
I don't know but it wouldn't surprise me if
there was. But there are
lots of other systems that use the same drives and tapes such as the HP
9845, 9835, 9825 calculator/computers along with LOTs of their test equipment.
The drive in this terminal, is it closer to the HP85 one ,or the HP98x5
one? The dismantling of those 2 types of drive is quite different, does
the terminal one come apart like one of them, or is it yet another type?
-tony
5 Feb
5 Feb
3:04 a.m.
On Sat, 4 Feb 2006, Tony Duell wrote:
construction as those for the HP85. The problem is
that the belt sticks
to the oxide layer on the tape, and/or the tape sticks together, and you
get major loss of the magnetic coating when you try to read the tape.
Needless to say this makes it unreadable.
So you try to shred a tape first and after that you begin to think about it?
Everyone who *knows* that the belt is sticking opens the cartridge and
tries to unstick the belt without damaging the tape. This works very fine
by applying heat (similar to baking sticky tapes, but here the tape is
not sticky, it's only the belt). And the tapes are fine afterwards. It's
how I revived all the original HP cartidges with software for the HP1000
(dated from 1980 to 1985) that I have. I've made backups, of course, but
they are still fine.
There are other tape cartridges that are really bad, notably DC-300 QIC
tapes from around 1977-1982. They have sticky belts *and* sticky tape
*and* a belt that will simply tear when the tape is moved.
Christian
9:37 a.m.
On Sunday 05 February 2006 03:04, Christian Corti wrote:
On Sat, 4 Feb 2006, Tony Duell wrote:
How do you heat them? How do you know when "enough is enough" heat?
Cheers,
Lyle
--
Lyle Bickley
Bickley Consulting West Inc.
Mountain View, CA
http://bickleywest.com
"Black holes are where God is dividing by zero"
construction as those for the HP85. The problem
is that the belt sticks
to the oxide layer on the tape, and/or the tape sticks together, and you
get major loss of the magnetic coating when you try to read the tape.
Needless to say this makes it unreadable.
So you try to shred a tape first and after that you begin to think about
it? Everyone who *knows* that the belt is sticking opens the cartridge and
tries to unstick the belt without damaging the tape. This works very fine
by applying heat (similar to baking sticky tapes, but here the tape is not
sticky, it's only the belt). And the tapes are fine afterwards. It's how I
revived all the original HP cartidges with software for the HP1000 (dated
from 1980 to 1985) that I have. I've made backups, of course, but they are
still fine. 
5:55 p.m.
Lyle Bickley wrote:
How do you heat them? How do you know when "enough is enough" heat?
heh. good question.
I've found that 130F is fine for most tape. Over 145-150F seems to
cause problems with the plastic housing & flanges (but the tape seems
fine).
At one point in time Ampex recommened 130F for baking. My experience is
that the RH in the area around the tape while at temperature has a lot
to do with getting the moisture out (which makes sense... pv=nrt)
I've baked tapes for as little as 7 hours and as long as 5 days. The
time does not seem to be as important as the RH around the tape.
-brad
6 Feb
6 Feb
1:23 a.m.
On Sun, 5 Feb 2006, Lyle Bickley wrote:
How do you heat them? How do you know when
"enough is enough" heat?
I take a lamp with a strong light bulb (ordinary 100W or a halogen lamp)
and hold the tape near the bulb. I constantly move the tape so there will
be no overheating at some spots. Actually you can see when the belt goes
from the sticky to the non-sticky condition. Before it
has a whitish
coating, when applying heat to the belt it gets black again and might
show
a shiny surface.
The advantage of this method is that you can see what is going on and
react accordingly.
Christian
9:07 a.m.
On Monday 06 February 2006 01:23, Christian Corti wrote:
On Sun, 5 Feb 2006, Lyle Bickley wrote:
Thanks!
Lyle
--
Lyle Bickley
Bickley Consulting West Inc.
Mountain View, CA
http://bickleywest.com
"Black holes are where God is dividing by zero"
How do you heat them? How do you know when
"enough is enough" heat?
I take a lamp with a strong light bulb (ordinary 100W or a halogen lamp)
and hold the tape near the bulb. I constantly move the tape so there will
be no overheating at some spots. Actually you can see when the belt goes
from the sticky to the non-sticky condition. Before it has a whitish
coating, when applying heat to the belt it gets black again and might show
a shiny surface.
The advantage of this method is that you can see what is going on and
react accordingly.
5 Feb
5 Feb
11:12 a.m.
On Sat, 4 Feb 2006, Tony Duell wrote:
Well _I_ don't, but plenty of other people do. I don't use these tapes if
I can help it
construction as those for the HP85. The problem
is that the belt sticks
to the oxide layer on the tape, and/or the tape sticks together, and you
get major loss of the magnetic coating when you try to read the tape.
Needless to say this makes it unreadable.
So you try to shred a tape first and after that you begin to think about it? Everyone who *knows* that the belt is sticking opens
the cartridge and
tries to unstick the belt without damaging the tape. This works very fine
by applying heat (similar to baking sticky tapes, but here the tape is
Thanks for the tip, I will give it a go on a couple of old HP85 tapes I
have (nothing rare, the stuff is already archived on the web, and I think
I have them on floppies anyway).
There are other tape cartridges that are really bad,
notably DC-300 QIC
tapes from around 1977-1982. They have sticky belts *and* sticky tape
*and* a belt that will simply tear when the tape is moved.
Any tips for dealing with those?
-tong
6884
days inactive
6896
days old
37 comments
14 participants
participants (14)
-
ard＠p850ug1.demon.co.uk -
bill_mcdermith＠mcdermith.net -
brad＠heeltoe.com -
cc＠corti-net.de -
cclist＠sydex.com -
glen.slick＠gmail.com -
gordonjcp＠gjcp.net -
jdbryan＠acm.org -
jfoust＠threedee.com -
lbickley＠bickleywest.com -
legalize＠xmission.com -
mloewen＠cpumagic.scol.pa.us -
rigdonj＠cfl.rr.com -
vp＠cs.drexel.edu