Chapter 14: What to do next?

When computer seems to work, look for program loading solutions. Maybe there is a program which converts software found in the Internet to WAV files which can be played to cassette tape? Or disk emulator package, like 64HDD for Commodore 64? If you have old tapes, digitalize them because they may degrade.
CP/M computers use floppy disks. With proper definition files, these disks may be read and written using 22DSK program and 5.25" disk drive in a MS-DOS computer.

Look for emulators of old computers. They allow to quickly test programs found in the Internet and see is it worth to make some copies for your machine. Sometimes emulators have quite sophisticated tools for tape I/O or data recovery. They usually allow to preserve states if you e.g. write a large program. For simpler emulators you may look at MESS project, which emulates lots of machines but has quite limited capabilities in their configuration and data recovery.

Some popular 8-bit microcomputers, like Commodore 64, still have lots of users and support in internet forums and communities. There are development environments for them running in a Windows-based PC, or cross-platform tools to compress data or load images.

Still (2016) in the Internet there are small websites offering DIY projects for some old computers. By analysing their schematics you can build some interfaces, monitor outputs or memory expansions for old computers. Sometimes you may find dead links to extincted sites, then Internet Archive is your friend. As today DIY is considered more like mental illness than a hobby, you may usually end in some archived site.

There are sites with software for old computers. For PC, look for "Vetusware" site. Commodore 64 games can be found in Gamebase64 or CSDB. For Atari, there is Atarimania. There is also a very big dump of software for many old computers called TOSEC, it is for many computers and targeted towards emulation. If you download some software from the Internet, you may need to convert it to format which can be written to disk or tape. Sometimes these comversions may be impossible, e.g. when having G64 file for Commodore 64 - such disk dump contains information about copy protection and it usually cannot be written to another 5.25" disk without loss of such information.

Updates?
And one more thing. If you plan to add some upgrades or expansions to the computer, do it carefully. Because modern electronics has shorter lifetime than older (Pb-free alloys, poor quality chips etc.), never cause irreversible changes to system's casing. Do not cut holes for additional buttons, because when the expansion will be damaged you will end with a computer with only an empty hole. If you plan to add some interface, use existing places for modules and expansions.
As an example, see the Basis 108 computer and its modern, PIC-based keyboard adapter. The module has been installed inside in a free space for some other expansions. The connection is made the way that the only thing to connect is to plug the ribbon cable into mainboard. External keyboard port is pulled out by one of free user's connectors. This way you can restore the computer to an original state by pulling the module off, re-connecting ribbon cable for DB25 keyboard connector and removing user connector's connections. Then you get a factory-state computer.

Storage
One more thing if you want to store old computers. The most important rule: If you removed the old computer from wet basement, don't put it back there after restoration.

- Place
The best way to store an old computer while not in use is in its box. If the box is not available, in any shelf keeping the computer in working position. Stacking micros one on another is a bad practice as keyboards may be damaged and, if some micro from between is removed, will certainly be damaged as keys are not designed to stand large shear forces. For smaller units like ZX81 or ZX Spectrum I use small, plastic chest of drawers originally sold for keeping stationery and documents (see photo).
For long-term storage, remove unneeded batteries (even CR2032 may leak in some specific conditions), park hard drive heads and, if possible, insert protective sheets to floppy disk drives. Add notes about configuration, HDD geometry, jumpers settings. After next 5 machines you will forget.
If you use original package, there must be something between styrofoam and computer, I prefer paper. Styrofoam packages tend to degrade and pollute plastic with white coating.
If computers are in desktop casings, you can stack them. The most important thing here is not to overload the bottom one and place old newspapers between them to avoid nasty marks in top of case from the bottom of above one.
Most notebook computers can be safely stored in a bookshelf, like books, if nothing is protruding from their sides. Just pick the side which will not cause connectors' covers to break off.

Conditionally acceptable form of storing notebooks
- Temperature
If you don't mess with a really old, tube-based machines, room temperature for storage is OK. Avoid large temperature amplitudes in short time. If the computer has magnetic media like hard disk, avoid temperatures below 10*C and don't even try to run the disk in low temperature as it will calibrate, calibrate and calibrate with expanding platter instead of running normal way. Floppy disks should be stored in boxes in vertical or semi-vertical position in room temperature. To maximize floppy disk life, store it in vertical position or tilted as in typical disk box, but not stacked one on another.

- Humidity
Room conditions are good for storing most machines. Some exceptions are really old mainframes with tube-based components and current regulating devices called U-Ox (whatever it is), which are extremely sensitive to humidity (releasing quite toxic chemicals), but they have been phased out in late 1950s. The most important thing is not to make computer "brew" in its humidity by packing it hermetically. For long-term storage silica bags should be avoided as not only silica is there - I've seen them leaving bad brown marks in places in which they were left.

- Sun light
Casings made of white or gray plastic are prone to being orange or brown with longer contact with sunlight, especially ultraviolet light. This process is irreversible. The ways to make it less visible include polishing the plastic or using strong oxidizers, which degrade plastic with time. The best way is just to avoid direct exposure for sunlight.

- Dust
This is the most trouble-free thing. Old computers are not XII-century paintings. If you vacuum-clean it every few months and the room is not visited every day, problem is in most cases solved. To vacuum clean it, use a soft brush with a long hair and don't use much vacuum pressure.

 

Archiving
Do not expect the floppy disks will stay for ever. Maybe you have the last survived copy of some rare old program? When dealing with old computers, you should archive data, software and firmware. Media in old computers are prone to damage, so archiving survived software is important.

1. EPROMS, PROMS
These chips are usually in sockets. Just pop them out and copy in programmer. There are many cheap devices which can read and write EPROMs, one of them is Willem programmer. And to read all EPROMs you don't need the last version (and it's discouraged as it's not compatible with many old EPROMs) - PCB3 is the last one which can read 2716 and 2732 EPROMs. Its technical documentation is available in the Internet.
To read PROMs you usually need some simple interface. The DIY IC Tester has routines to read some PROM chips. PROM chips rarely fail (as programming them is literally blowing a small fuse inside) so if you don't plan to analyse the machine in emulation scope (i.e. to write the emulator) copying PROMs is not essential.
If EPROM is soldered in, desoldering may damage it. Theoretically it is possible to connect, using special clip, a TTL logic analyzer to it and just get the data from working computer. Next, data dump is analysed using script to get data lines state from address lines state with proper combination of /CS and OE lines. However, I haven't seen such solution in practice.

2. Cassette tapes
First of all, you should look for programs which dumps cassette tape WAVs to some machine-characteristic files. They usually require WAV file from cassette and output ready programs for microcomputer, so these programs can be used e.g. in emulator. In C64, it is possible to convert tape to PRG files, which are programs and, if cassette is in non-program format (most original games) to TAP file which is a narrow signal format, like WAV specific for cassette data. If there is no software at all, dump WAV files. They always can be played back. And don't use too high specifications for WAV file. 48bit, stereo and 88200kHz is not needed, use mono signal, 16 bit (although 8 is usually good too) and usually even 22050Hz is OK. Now about format. Use losslessly-compressed WAV. Not MP3, OGG, FLAC, just WAV. They are larger, if you want to send them by e-mail just compress them with 7-Zip or similar. WAVs can be played almost everywhere, so it is possible to use e.g. cheap MP3 player to feed the program to microcomputer. This is not possible with lossless FLAC as most cheap players don't support it.

3. Floppy disks
Use solutions related to your microcomputer. For Commodore, it's Star Commander and cable connecting 1541 drive. There is a plenty of ways a typical 5.25" floppy disk can be formatted and microcomputers use different methods of formatting it even with placing bits using magnetic field - While PCs and similar use modulation method called MFM, Amiga and Commodore 64 use GCR, so PC drives will not reliably read the disk.
Make an image of a whole disk if you can. Disk image is handy and allows to analyse not only what is on the disk, but in many cases what has been removed from it. Disk image will deal with simple copy protection mechanisms.
There are commercial and very expensive solutions like KryoFlux, which read a whole disk to a forensic track-by-track format, and they can deal with most copy protection methods as the result is what floppy disk drive "sees" on the disk.
In Commodore 64, it is possible to use Burst cable (see http://sta.c64.org/xxp1541c.html) to create G64 image. This image can't be recorded back to the disk, but it contains most copy protection mechanisms in a form the drive's head sees it - so it works in emulator.

4. Hard disks
If the machine is not a PC, you usually have a proprietary format. Try to get important things on a floppy, as it's easier to take it from the computer. If you are sure that the disk will live for more time, use compression software to create "packages" with programs. As always, there are disk imaging solutions but they are expensive and proprietary.

5. Other media
Paper code listings may be just scanned. For continuous paper I found that there are battery-powered "line scanners" which do their job well if only the surface is flat and the sheet is thin.
If you have other stoarge devices, such as streamers, it is needed to move the data or image the media using target machine. If a streamer works using known protocol with serial port, you can try to make a program which drives it and reads the tape to image. The exception are Unix workstations which usually have some dd, so you are ready.
After getting the programs from the computer you got, remember to sanitize it by removing previous user's documents if they are present - these files are not needed and only waste space. Make sure to check is it working e.g. in emulator as by accident some part of program may be skipped in archiving process.


I hope you found these informations useful. Good luck with a new old computer!

MCbx, 2016

Chapter 13: Mainboard
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MCbx, 2016