31 Mar
1997
31 Mar
'97
12:01 p.m.
I was talking to a friend this weekend who brought
up this idea that before long EPROMs in our old
computers are going to start to go bad. This is
something I've heard before but, to be honest, I
don't know enough to make a judgement on it. If
this is the case, I suppose I should be burning
backups.
While I'm at it... What are some other concerns
along these lines. What should we be planning
for as these machines grow 5, 10, 15 years older?
Bill Whitson
ClassicCmp "owner"
bcw(a)u.washington.edu bill(a)booster.u.washington.edu
28 Mar
28 Mar
12:54 p.m.
It was thus said that the Great Bill Whitson once stated:
While I'm at it... What are some other concerns
along these lines. What should we be planning
for as these machines grow 5, 10, 15 years older?
Replacement parts. One of the newsgroups I follow (which is a shadow of a
mailing list) there was major concernt over the availability of floppy drive
controller chip (the 1773 I think). That particular chip isn't being made
anymore.
Also, on the subject, floppy disks. I've heard they have a shelf life of
approximately 10 years, but so far (knock on formica) I've been lucky
(although out of a box of 10 8" disks, only three were good).
-spc (Oh, don't forget lack of documentation - I have tons of PC cards
that may well be perfectly good, I just don't know how to set
them up ... )
1:20 p.m.
Yes, "bit rot" is a indeed an actual problem for cartridges and machines
that use EPROMs. I've been collecting Atari 2600 and other videogame
cartridges for a while now and collectors in that community have been
dealing with it for a while.
I'm not an electrical engineer, but as I understand it, it's not an
actual problem with the hardware of the machine itself. It's just that
the magnetic alignment in the EPROM (erasable programmable read only
memory) disintigrates. However if you have a backup of the chip, it can
be re-programed using an EPROM burner.
I know that for Atari 2600 cartridges, only prototype and low-quality 3rd
party cartridges were made with EPROMs in them. I'd be surprised if any
machines actually use EPROMs to store the ROM kernels, but perhaps they
do. If so, a list of affected machines should be made. Perhaps I should
crack open the cases on the machines in my collection when I go back to
Texas and see if any of them have EPROMs in them.
While I'm at it... What are some other concerns
along these lines. What should we be planning
for as these machines grow 5, 10, 15 years older?
I've always wondered about the use of electrolytic capacitors in
computers. I believe that these buggers go bad after a while and need to
be replaced. Is this true?
I've also always been concered about floppy disks going bad. Do they
have a definately lifespan? If so, it might be hard to find new 5.25", 8"
or 3.25" (a la Amstrad) disks on which to copy ailing files.
chris starling
3:20 p.m.
Dunno about roms and eproms, but I have radios that are 50 years old and yeah,
electrolytic caps do have a finite lifespan. They dry out. Mind, these are
the old wax-cardboard wrapped kind and not the kind in the metal cans. But
unless you're dealing with eniac and it's tube fired bretheren I'd not yet
worry about your caps - or your resistors - yet. Also bear in mind that tube
radio equipment gets a lot hotter than your computer does inside (right?)
--
Jim Strickland
jim(a)calico.litterbox.com
--
By Caffeine alone my mind is set in motion.
Through beans of java thoughts acquire speed, the hands acquire shakes.
The shakes become a warning - I am in control of my addiction!
By Caffeine alone my mind is set in motion.
Adapted from the Mentat chant of _Dune_
2 Apr
2 Apr
12:53 p.m.
[EPROMs]
I'm not an electrical engineer, but as I
understand it, it's not an
actual problem with the hardware of the machine itself. It's just that
the magnetic alignment in the EPROM (erasable programmable read only
Actually, it's an electrostatic charge that leaks away. The effect is much
the same, though - the chip can be reprogrammed, and works fine. It just
forgets the data that should be in it.
But chips (_all_ chips) can and do fail. So I'd recomend backing up ROMs,
PROMs (the fusible-link type used for address decoders, state machines,
etc), PALs, etc. Everything.
memory) disintigrates. However if you have a backup
of the chip, it can
be re-programed using an EPROM burner.
I know that for Atari 2600 cartridges, only prototype and low-quality 3rd
party cartridges were made with EPROMs in them. I'd be surprised if any
Yes, but ROMs can fail as well. You should still keep backups.
machines actually use EPROMs to store the ROM kernels,
but perhaps they
do. If so, a list of affected machines should be made. Perhaps I should
Classic PERQs have an EPROM on the I/O board for the Z80 code. PERQ 3a's
have the bootstrap in EPROM. I've got DEC-compatable boards with EPROMs on
them. I'm sure a lot of other machine have EPROMs in them - particularly
the machines made in smaller quantities - which are therefore rarer, and
more important to preserve.
Remember that an EPROM need not be in a ceramic package with a quartz
window. OTP (One Time Programmable) EPROMs are in a normal plastic
package. They can't be erased by UV light (there's no way for it to reach
the actual chip), but they program just like EPROMs, and they suffer from
bit-rot just the same. If in doubt, back it up.
I've always wondered about the use of electrolytic
capacitors in
computers. I believe that these buggers go bad after a while and need to
be replaced. Is this true?
Well, it's not a real problem. I've had exactly one big electrolytic fail
in _all_ my computers (and I have machines over 25 years old). That one
was in a PDP11/44, and was damaged when the PSU overheated (amazingly, it
was the only damage!).
But capacitors are standard parts. Unless you insist on only using the
original manufacturers components, it's not hard to find replacements for
them. I don't worry about that at all.
I've also always been concered about floppy disks going bad. Do they
have a definately lifespan? If so, it might be hard to find new 5.25", 8"
or 3.25" (a la Amstrad) disks on which to copy ailing files.
Yes, disks do go bad after a time, alas. The only compensation is that the
older disks (particularly 8") seem to last a lot longer than the modern
3.5" ones.
chris starling
--
-tony
ard12(a)eng.cam.ac.uk
The gates in my computer are AND,OR and NOT, not Bill
31 Mar
31 Mar
12:45 p.m.
Hi Bill,
I was talking to a friend this weekend who brought
up this idea that before long EPROMs in our old
computers are going to start to go bad. This is
something I've heard before but, to be honest, I
don't know enough to make a judgement on it. If
this is the case, I suppose I should be burning
backups.
This is something about which to worry.
While I'm at it... What are some other concerns
along these lines. What should we be planning
for as these machines grow 5, 10, 15 years older?
My other worry is storage. Magnetic tapes and disks do not last forever.
Hard disks do not last forever. How long until the last 8 incher finally
gives up the ghost and sheds all of its bits? I know that there are still
a few places which sell them, but how much longer will they be manufactured?
How long until the last MFM hard drive wears out?
Most manuals were not printed on acid free paper, how long until they
start to turn to dust?
How long do cassette tapes last?
In 50 to 100 years how many of the machines that run fine today will
not be usable because there are no disks on which to store programs or
data?
I have come across some solutions, though none of them are really
optimal:
Use a PC with a high grade sound card to store and load cassette data to
older machines. I don't personally know if anyone has really done this.
Store critical data (ROM images) on punched mylar tape.
Store disk images on CDROM. (How long do these last? I've heard 50
years, can anyone confirm this?) This has the problem of moving the
data from the CD to the target machine. I don't think that my PX-8
can understand ISO 9660 file systems.
For the near term we can backup every disk we acquire. Pull out the
old machines at least once a year and make new backups. Stockpile
anything which will wear out. Keep everything clean, out of direct
sunlight, and within a reasonable temperature range.
Anyone have any really good long-term solutions for the preservation
of our machines?
--pec
--------------------------------------------------------------------------
2:20 p.m.
At 06:45 PM 3/31/97 -0800, you wrote:
Use a PC with a high grade sound card to store and load
cassette data to
older machines. I don't personally know if anyone has really done this.
Good idea! I have not tried it but I think it should work. After you made
the recordings, you can burn the sound files onto CD-ROMs for permanent
archive.
I know there are some computer emulators that do the opposite. You play
your old cassette data through the sound card and the emulators will decode
the "noise" into bits.
George
--
George Lin "Accelerating your business through
Network Architect, MIS enterprise document managment."
Documentum, Inc. (Nasdaq: DCTM) http://www.documentum.com
Inet Fax: mailto:remote-printer.George_Lin@4.3.8.6.3.6.4.0.1.5.1.tpc.int
My PGP Public Key for encryption is at http://george.home.ml.org/pgp.htm
28 Mar
28 Mar
4:24 p.m.
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1 Apr
1 Apr
5:19 a.m.
On Mon, 31 Mar 1997, Paul E Coad wrote:
My other worry is storage. Magnetic tapes and disks
do not last forever.
Hard disks do not last forever. How long until the last 8 incher finally
gives up the ghost and sheds all of its bits? I know that there are still
a few places which sell them, but how much longer will they be manufactured?
How long until the last MFM hard drive wears out?
Amazingly, all my Apple software starting from the mid-80s is still
functional. I used to pull each disk out and test for errors every now
and then but I haven't done this in probably 5 years. Recently I've been
playing with my Apple again and all my software seems to be still in
tact, but I worry about them degrading. I hope to transfer them all to
disk images on my PC (hopefully soon) so that as a side benefit I can
enjoy them on my emulator. I'm amazed that the disks are still sound
since I used to buy those bulk diskettes that you could get through
catalogs like Computer Direct ($.19 in quantities of 50). Those weren't
the best quality diskettes, or were they?
I also have a Sider ][ harddrive for my Apple that was probably
manufactured in 1984 or 1985 and it's still running fine (knock on
everything). Imagine that...a 12 year old MFM harddrive still going
strong. It used to run a BBS early on so its seen some days.
Most manuals were not printed on acid free paper, how
long until they
start to turn to dust?
Photocopy!
How long do cassette tapes last?
Make copies!
In 50 to 100 years how many of the machines that run
fine today will
not be usable because there are no disks on which to store programs or
data?
I was just thinking of this the other day. I haven't booted any of my
classic computers in a couple years. I'm afraid that the next time I
fire one up the circuits won't be able to handle the sudden current and
will fry. I was wondering if there was some way to start them off with
an undercurrent for a second or so and then go to full voltage. I don't
know if this is feasible or even recommended. Will this do more harm
than good?
I have come across some solutions, though none of them
are really
optimal:
Use a PC with a high grade sound card to store and load cassette data to
older machines. I don't personally know if anyone has really done this.
Good idea. Basically you are just sampling the cassette audio signals
and storing them on your PC hard drive.
Store critical data (ROM images) on punched mylar
tape.
I would simply store these as a disk image on a PC as well.
Store disk images on CDROM. (How long do these last?
I've heard 50
years, can anyone confirm this?) This has the problem of moving the
data from the CD to the target machine. I don't think that my PX-8
can understand ISO 9660 file systems.
Serial communications. Read each block of data from the source data
medium and transfer over the source's serial ports (if it is lucky enough
to have one) to your PC.
For the near term we can backup every disk we acquire.
Pull out the
old machines at least once a year and make new backups. Stockpile
anything which will wear out. Keep everything clean, out of direct
sunlight, and within a reasonable temperature range.
Good idea. I would also suggest using compressed air to blow out any
dust should your systems be exposed to any. I have most of my smaller
classic computers wrapped in anti-static bags that I got from worked and
then packed them in cardboard boxes with packing foam and taped up the
boxes. Snug as a bug.
Anyone have any really good long-term solutions for
the preservation
of our machines?
Put them in stasis like in Star Trek. Store them in a vacuum. Clone
them like sheep.
Sam
-------------------------------------------------------------------------------
Computer Historian, Programmer, Musician, Philosopher, Athlete, Writer, Jackass
2 Apr
2 Apr
3:28 a.m.
In article <Pine.SUN.3.91.970331180928.17082A-100000(a)crl.crl.com>om>, Paul
E Coad <pcoad(a)crl.com> writes
Store disk images on CDROM. (How long do these last?
I've heard 50
years, can anyone confirm this?)
If you mean CD-Recordable, the green dye ones are 75 years, the gold dye
ones are 100 years claim the manufacturers. Remember, this is by
accelerated testing, so factors can probably change to alter these
figures.
However, the onrecorded shelf-life of the blanks is only 10 years.
Data available from the CD-R FAQ at
http://www.cd-info.com/CDIC/Technology/CD-R/FAQ.html
--
Martin Evans at
Whitfield Street Studio, London
12:42 p.m.
I was talking to a friend this weekend who brought
up this idea that before long EPROMs in our old
computers are going to start to go bad. This is
something I've heard before but, to be honest, I
don't know enough to make a judgement on it. If
this is the case, I suppose I should be burning
backups.
Don't bother with burning backups (after all, the backup will only last
another 10 years), but dump the data (as a plain binary file) to a
suitable archival storage medium.
What I recomend is _before_ even powering up a machine is to dump all the
ROMs, the PALs (an amazing number of classic computers have
non-copy-protected PALS), etc to a PC-format disk. Then punch any really
rare stuff onto paper tape (You may laugh, but I've _never_ found a paper
tape that I can't read, and EPROM files are not that big in general). If
the chips ever fail in the future, then It's easy to burn a new EPROM
then.
While I'm at it... What are some other concerns
along these lines. What should we be planning
for as these machines grow 5, 10, 15 years older?
Well, there's no problem with standard electronic parts (resistors,
capacitors, TTL chips, etc). I don't think you'll have any problems
finding those in 15 years time.
Other chips are more of a problem. AMD2900 bit-slice chips are getting
hard to find, and a lot of minicomputers and their peripherals depend on
them. But I'm not sure that if I buy any now they'll still be good in 10
years time.
ASICs are a big problem. Basically, there's no hope if they fail. You
can't copy them at home. The best thing to do is to figure out _exactly_
how they work, the timing of all the signals, etc, and to record that. If
the chip fails, and you can't get one, then at least you can make a clone
out of TTL or something like a Xilinx FPGA.
I'd also recomend recording any information now that would be of use if
the machine failed. If you know what you are doing, note down the voltages
on the CRT electrodes in a monitor. The waveforms in the PLL of a disk
controller, that sort of thing. Basically, annotate the service manual
with details of _your_ machine.
Bill Whitson
ClassicCmp "owner"
bcw(a)u.washington.edu bill(a)booster.u.washington.edu
--
-tony
ard12(a)eng.cam.ac.uk
The gates in my computer are AND,OR and NOT, not Bill
10125
days inactive
10127
days old
10 comments
10 participants
participants (10)
-
ard12＠eng.cam.ac.uk -
bill＠booster.bothell.washington.edu -
dastar＠crl.com -
george.lin＠documentum.com -
jim＠calico.litterbox.com -
lists＠phx6.phxmedia.com -
MARTIN＠paladio.demon.co.uk -
pcoad＠crl.com -
spc＠armigeron.com -
starling＠umr.edu