=============================================================================
ClassicCmp - The Classic Computers Discussion List
Part 3 in the ClassicCmp FAQ Trilogy
Technical FAQ (Frequently Asked Questions) v1.6.2
Last Update: 12/10/97
-----------------------------------------------------------------------------
This FAQ is written with the primary purpose of making readily available
answers to the more common questions appearing on ClassicCmp. It is
Maintained by Bill Whitson <bill(a)booster.u.washington.edu>. The infor-
mation in this document has been gathered from a variety of sources but,
in general, the members of ClassicCmp should be credited for all contain-
ed herein. I have, of course, endeavored to be as accurate as is possible
and often failed ;).
This FAQ is Part 3 of the ClassicCmp FAQ Trilogy. The information presented
deals with regularly asked questions which are technical in nature.
If you have questions, comments, or corrections (always welcome) please
contact me at the address above.
A current copy of this FAQ is available on the web at http://haliotis.bothellwashington.edu/classiccmp or via anonymous FTP at 140.142.225.188 in the
directory /pub/classiccmp/faqs as cclpart3.faq.
-----------------------------------------------------------------------------
Updates: Nothing new, cosmetic changes.
-----------------------------------------------------------------------------
1. General
------------------
1.1 I just picked up a new machine. What should I do?
1.2 What's the best way to clean these dingy tan boxes?
2. Media
--------
2.1 What's a hard sector disk? What's a soft sector disk?
2.2 What's SS/SD, DS/DD, DS/QD, DS/HD, etc.
2.3 Can these formats be interchanged?
2.4 What disk sizes are there?
2.5 How do I take care of old media?
3. Component Failure Issues
---------------------------
3.1 Do EPROM's go bad?
3.2 How about ROM's, other chips?
3.3 How about capacitors?
3.4 Anything else?
3.5 So how do I backup all this stuff like you suggest?
4. Software
-----------
4.1 Where can I get a system disk for platform X?
4.2 What's the best way to back up my software?
5. Specific Problems/Solutions
------------------------------
5.1 Is it possible to bypass an RF modulator to achieve composite output?
=============================================================================
1.1 I just picked up a new machine. What should I do?
Don't power it up yet! All of the following should probably be done
before that power switch gets flipped.
Open the case - clean and visually inspect components. You're
looking for traces of smoke, water, corrosion, loose screws, blown
caps and resistors, cold (broken) solder joints, bent pins, etc. It
may be a good idea to remove and re-seat all socketed components and
connectors. If anything burned or overheated it will probably pay to
replace it before powering up the unit. You can avoid a number of
problems just by taking a peek inside.
If you have the tools (and the machine is sufficiently rare) pull and
dump backups of all EPROMs, ROMs, and PALs. If you have really cool
tools (like a logic analyzer) it has been suggested that you use them
to record critical information from those oh-so-hard-to-find custom
chips. Specific information on how to do this is beyond the scope of
a FAQ, but you probably know what you need to if you own the appropriate
tools.
Disconnect the power supply from the rest of the computer and start it
up on a "dummy load". A six volt headlight bulb has been recommended as
a convenient load. These should be available from any decent Volkswagen
shop. Running the power supply without a load could result in damage to
it. You may want to check the voltage output before you do this as it
could be no where near the 5V average in micros. Even if you don't want
to connect a load it's still probably a good idea to power it up
separately from the computer for the first time. If you have a really
rare beast it may be worth powering up some of the key capacitors out of
circuit just to get them warmed up.
Now you can power it up. Assuming it works, take a blank disk,
format it, write some data to it, and read it back before using your
precious software with it, as a bad disk drive could really ruin your
day.
1.2 What's the best way to clean these dingy tan boxes?
Cases: It seems best to start gently with such old equipment. Try
soaking in a little water and dish soap and then scrubbing. This takes
care of most jobs. For removing stickers try mineral oil or Goo-Gone
(available at most hardware stores - in the US at least). If those
don't work, acetone can be good but, if overused, can do more harm.
For removing marker, almost any solvent is good (alcohol, naptha, etc)
but will definitely discolor or dissolve plastic if not carefully
applied. Lava soap is also good for removing marker but can smooth off
textured plastic. For removing sun or tobacco discoloring a product
called Purple Stuff available from auto parts stores (again, in the US
at least) seems to do the job almost effortlessly.
Recommended commercial products:
Purple Stuff from Kragen [for discoloration]
Brasso [ink/marker] (can discolor plastic)
Antistatic Foam Cleaner from Electrolube [for discoloration/markings]
Citra-Solv [for discoloration] (can dissolve plastic if undiluted)
Cameo Copper Cleaner [ink/marker]
Naptha [for stickers/goop/spooge] (very flammable)
3M GP Adhesive Remover [for stickers/goop/spooge]
CRC 226 / CRC 556 [for stickers/goop/spooge]
Fulcron [for discoloration]
Blue Shower / BS II [for stickers/goop/spooge]
Connectors: For edge connectors a plain pink eraser seems good
for removing corrosion. Apparently other colors of eraser indicate a
different texture - which may be damaging. Make sure to wipe the
connectors with a clean cloth after erasing on them. There are a large
number chemicals on the market that "magically" remove corrosion from
components but as I don't know how safe they are, I'm not anxious to
promote any of them. For pin style connectors a toothbrush and some
softscrub or other mildly abrasive cleaner do wonders.
Recommended commercial products: Electrolube contact cleaning sprays.
Keyboards: I find a cycle through the dishwasher does a really nice
job on keyboards. Just be sure they're completely dry before you
put any power to them. If there is reason not to use a dishwasher
(some key labels can come off) it is usually possible to remove each
keycap and clean conventionally.
[][][][][][][][][][]
2.1 What's a hard sectored disk? What's a soft sectored disk?
We'll start with soft-sector since they're simpler to explain. On a
soft-sector floppy disk the information that marks where a sector
begins and ends is written to the disk by the computer (part of the
formatting process). This means that various computers can use
the same floppy disk types because the format of the disk is control-
led by the operating system.
Hard sector disks use a system of perforations in the media to mark
the beginnings and ends of sectors. This means that computers
which used hard sectored disks required the exact disk type they
specified rather than a generic soft-sector floppy. A number of
differently sectored disks were available - at least 10, 13, and 16
sector formats. 8 inch and 5.25 inch disks commonly used hard
sectoring. 3.5 inch disks never came hard-sectored and, in fact,
it would not be possible.
2.2 What's SS/SD, DS/DD, DS/QD, DS/HD, etc.
These all refer to the number of useable sides on a disk and it's
density (how "efficiently" the magnetic bits are pushed together).
SS/SD is a Single Sided - Single Density disk, the earliest available
type I believe. The storage afforded by a single density disk was
very small compared to today's standards. Single Sided disks were
popular because they were cheaper than DS and could be easily
modified with a hole punch into double sided disks. SD was followed
by Double Density which, amazingly, doubled the amount of storage
space. Double Density was followed by the extremely short-lived
Quad Density which doubled a DD disk. QD was short lived because
High Density was right on it's heels and nearly doubled disk capacity
again. DS/HD was as sophisticated as 5.25" disks became. 3.5"
disks have progressed as far as DS/EHD double-sided / extra-high
density.
2.3 Can these formats be interchanged?
Well, that may depend on what computer you are using, but in general
the following substitutions may be made:
Desired Format Substitute
---------------------------------------------------
Single Density Double Density
Double Density none reliably
Quad Density DD, HD (sometimes work, not advisable!)
High Density none
Other substitutions may be made, but due to physical differences in
how the disks are made they are generally unreliable. It can almost
be guaranteed that data written to a proper density disk of poor quality
will last longer than data written to a good quality disk of the wrong
density. In the case of quad density no substitution should be
considered reliable. DD and HD disks both can be forced to work. One
may work better than the other given the peculiarities of various drives.
2.4 What disk sizes are there? Disk Types?
Physically?
Standard Disks Unique/Proprietary Disks
---------------------------------------------------------
8" (Floppy) 5" (MiniFloppy)
5.25" (MiniFloppy) 3.25" (MicroFloppy)
3.5" (MicroFloppy) 3" (MicroFloppy)
2.5"
2"
In addition to odd sizes - there is at least one type of disk which
was physically different. "Twiggy" disks for the Apple Lisa 1 were
regular 5.25" disks with the exception that they had two read/write
windows. One was oriented "north" of the center hole, the other "south".
2.5 How do I take care of old media?
Step one is Back It Up! After that, make sure it's kept in a clean, dry,
temperature-controlled environment (I keep mine in a broken freezer).
With disks it seems important to keep them standing on end rather than
lying flat - the same goes for cassette tapes. I like to exercise disks
and tapes at least once every six months although I have no real
evidence that this has any positive effect. I have modified an old C64
floppy drive to simply spin when a disk is inserted and send large
stacks of disks through it on a regular basis just to make sure they're
not starting to stick up internally.
An exciting and somewhat recent development is that availability of
classic computer emulators that can make disk images of old media
on PC's and Macs. This seems to be a very good way to backup
disks since they will eventually go bad no matter how well we take
care of them.
The official line seems to be that floppy disks have a shelf-life of
approximately 10 years. With proper care many are lasting a lot longer.
[][][][][][][][][][]
3.1 Do EPROM's go bad?
Definitely. They apparently are considered to reliably contain data for
(on the outside edge) 15 years. This amount can be considerably
reduced if, for example, the sticker over the window has dried out and
fallen off. Luckily EPROMs were not used too extensively but they're
out there. An EPROM writer/reader is a relatively cheap investment
and an easy fix. Even if an EPROM has "forgotten" it's data it is still
fine for being "re-educated".
3.2 How about ROMs and other chips?
Things wear out. It's likely that even components which have not been
fried by catastrophic failure will simply start to die someday. ROMs can
be dumped to a file and re-written if they die. Other custom chips which
are all too common in micros will be far more difficult to replace. The
best advice is to stockpile these chips when you can - but someday even
unused chips will probably start to turn up bad. In this case the best
defense is to stockpile information in the hope of being able to modify
an existing component to meet your needs.
3.3 How about capacitors?
This seems to be another large concern, but rather than being an
unreplaceable component a capacitor will take your unreplaceable
components with it when it goes. It's a good idea to check out all the
caps in a system if you haven't fired it up in a while. Caps go bad
with time (even tantalum caps, apparently - although they are more
reliable) and should be replaced if they are suspect. It's unlikely that
it will be impossible to find a replacement capacitor as they are much
more standard electronic components.
3.4 Anything else?
Documentation: If there's anything which is entirely unreplaceable its
the docs for uncommon equipment. Once they're gone, they're gone.
I regularly pick up docs I find for equipment I don't have just because
I may someday. Paper will, of course. go bad over time but it will be
obvious and they will be easily duplicated.
Hard Disks: ST-251s, ST-502s, MFM, RLL... old hard disks are going
to go bad. Then they'll be gone. Theoretically, I suppose it's possible
to crack a hard drive and replace a dead bearing, realign, relaminate,
etc... but I've never heard of anyone doing these things in their base-
ment. Perhaps in another 5 or 10 years many of us will be experts at this.
3.5 So, how do I back up all this stuff like you suggest?
This answer will undoubtedly get longer as I learn more. The best ways
seem to be to dump the particular ROM (or whatever) using the approp-
riate equipment to a floppy disk (which most of this equipment allows).
Yes; but then I'd have to ship the controller cards as well. These only
have the 5 1/2" (or whatever) drivebays; the ones that fit the XTs; etc. I
think that they're half-height.
-----Original Message-----
From: Don Maslin <donm(a)cts.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Thursday, December 11, 1997 1:25 AM
Subject: Re: Donation For School Wanted
>On Wed, 10 Dec 1997, PG Manney wrote:
>
>> Sent where?
>>
>> Since those are 286's, they could be outfitted with cheapo IDE's such as
>> ST-157's and 125's as well...IDE paddle cards are common.
>>
>Actually, that is probably the smarter thing to do. Smaller drives, less
>shipping weight and less postage. Also newer than MFM/RLL and more
>readily available, and about equally inexpensive.
>
> - don
>
=============================================================================
DO NOT DISPOSE OF THIS PART OF THE FAQ. THIS IS THE PART THAT EXPLAINS HOW
YOU CAN SUBSCRIBE AND UNSUBSCRIBE. IT WILL TAKE ME MORE TIME TO DO THESE
THINGS FOR YOU THAN IT WILL TAKE FOR YOU TO DO THEM YOURSELF
=============================================================================
ClassicCmp - The Classic Computers Discussion List
Part 1 in the ClassicCmp FAQ Trilogy
Mail/Internet Basics FAQ (Frequently Asked Questions) v1.3
Last Update: 12/10/97
-----------------------------------------------------------------------------
This FAQ is written with the primary purpose of making readily available
answers to the more common questions appearing on ClassicCmp. It is
Maintained by Bill Whitson <bill(a)booster.u.washington.edu>. The infor-
mation in this document has been gathered from a variety of sources but,
in general, the members of ClassicCmp should be credited for all contain-
ed herein. I have, of course, endeavored to be as accurate as is possible
and often failed ;).
This FAQ is Part 1 of the ClassicCmp FAQ Trilogy. The information presented
deals with the use of mailing lists and internet-specific tools.
If you have questions, comments, or corrections (always welcome) please
contact me at the address above.
A current copy of this FAQ is available on the web at http://haliotis.bothellwashington.edu/classiccmp or via anonymous FTP at 140.142.225.188 in the
directory /pub/classiccmp/faqs as cclpart1.faq.
-----------------------------------------------------------------------------
Updates: Nothing new, cosmetic changes.
-----------------------------------------------------------------------------
1. Mailing Lists
----------------
1.1 Mailing List Basics
1.2 How to Talk to the Robot
How to set to Digest
How to Subscribe
How to Unsubscribe
2. FTP
------
2.1 FTP Basics
3. World Wide Web
-----------------
3.1 WWW Basics
=============================================================================
1.1 Mailing List Basics
A mailing list is a simple device which takes an e-mail and redistributes it
to a group of people. People can add and remove themselves from the
distribution list by Subscribing and Unsubscribing. When you send a message
to the list, it is first examined by the robot for key words that tell it
to process an automatic funtion (like help, subscribe, unsubscribe, etc).
If the message does not contain a keyword it is sent to the distribution
list.
1.2 How to Talk to the Robot
There are a few List Processor commands that you might want to use. To
send a command to the list processor, write a message to
listproc(a)u.washington.edu
(Do NOT send the message to classiccmp(a)u.washington.edu). In the body of
the message (not the subject line, that is) write one of the following
commands, then send the message.
SET CLASSICCMP MAIL ACK
Tells the robot to send you a copy of messages you
write to the list. This is the default.
SET CLASSICCMP MAIL NOACK
Tells the robot NOT to send you a copy of messages
you write to the list. I don't recommend this.
SET CLASSICCMP MAIL DIGEST
Tells the robot to send you a digest of messages
rather than each as it is posted. With this option
you will get a weekly bundle of messages and keep
a nice, tidy in-box.
SUBSCRIBE CLASSICCMP Your.Address
Subscribes you to the list.
UNSUBSCRIBE CLASSICCMP Your.Address
Removes you from the list.
[][][][][][][][][][]
2.1 FTP Basics
FTP is a protocol by which files can be transferred over the internet.
You can use FTP to connect to a remote site and retrieve files. The
commands you use with FTP depend on the software you use. In general
you must make sure that you are in BINARY mode before transferring a
program file or compressed files. The process of downloading a file
is usually termed GET and the process of uploading a file is usually
termed PUT.
Your FTP program will require an address to connect to. For the
ClassicCmp site that address is 140.142.225.188.
You then may be asked to log in (unless your program assumes an
anonymous login). When asked for a name, use anonymous. When asked
for a password enter your internet e-mail address.
[][][][][][][][][][]
3.1 WWW Basics
The only complicated thing with the WWW is knowing what bells
and whistles your web browser supports. You don't really need to
know much other than the address for ClassicCmp. The web site is
all text which means just about any web browser from the oldest
Lynx to the newest Netscape or Microsoft browser should support it.
The ClassicCmp site is http://haliotis.bothell.washington.edu/classiccmp.
=============================================================================
Hi all.
I haven't been around much for the past
few months and I know I left some of you
in a lurch in the middle of projects. My
work situation has been largely resolved
and I am about to begin a long vacation, so
here's a good time to ask if you need
anything from me.
If I've missed anything really cool, let
me know ;)
-------------------------------------------------
Bill Whitson bcw(a)u.washington.edu
(mail may come from alternate addresses)
Classic Computers List Operator/Owner
http://haliotis.bothell.washington.edu/classiccmp
Sent where?
Since those are 286's, they could be outfitted with cheapo IDE's such as
ST-157's and 125's as well...IDE paddle cards are common.
----------
> From: classiccmp(a)u.washington.edu
> To: Manney
> Subject: Donation For School Wanted
> Date: Wednesday, December 10, 1997 12:01 PM
>
> Hello. After paying a visit to the only local High School; someone made
a comment about how their 286's didn't work. From an inspection of the
school; it looks like 486's are used in half the labs; 2-4 286's and 1 386
per class room; and the process of Pentiums is being integrated. Some in
the most recent wing do have one. But anyway; the 286s; as you might
guess... are DYING. These are all PCs; and the problem is in HDDs. Now; I
only have one MFM HDD handy; which I'll be installing soon; but there are 2
other malfuctioning PCs that I know of. Remember; this is for a high
school; for the Department of Defence dependants; and a few others, but
their funding is not... ideal. So if you could please just send a MFM HDD,
or; if you have them; two (probably of the 20-40MB vairety; the standard
sofware is a DOS menulite; WP51 for DOS; Qbasic; Printshop; etc. so it's
not heavy; but for DOS 5.0 (what they have) I'd guess that a 10MB would be
pushing it.); and then you'ld have elementary and high school (it's m
<Printshop; etc. so it's not heavy; but for DOS 5.0 (what they have) I'd =
<guess that a 10MB would be pushing it.); and then you'ld have elementary =
I've an xt with a 20mb running dos6.22 and a bunch of stuff similar in size
including wordperfect works and theres about 10mb free at the moment.
DOS6.22 eats 5.0mb for EVERYTHING and goodly portions can easily be deleted
to get to under 2mb. Dos 5.0 is smaller so 10mb is a serviceable though
possibly cramped disk. 6.22 however also give you drivespace a disk space
compressor like smartdrive so that the space can be better used.
Allison
----------
> From: classiccmp(a)u.washington.edu
> To: Manney
> Subject: Re: Breach in subject
> Date: Tuesday, December 09, 1997 9:15 PM
>
> At 09:48 PM 12/9/97 -0500, you wrote:
>
> >Try Global. They have _everything_.
>
> Global what? Please don't make me do a search on "Global"!!!! :)
Global computer Supply. I have the number at work (They've got an 800
number...call 1-800-555-1212 to get it). Once you're on their mailing list,
tho', you get 100 catalogs a year.
They have all kinds of oddball stuff (Rainbow disks, last I checked, for
example.)
