Motherlode of Tapes

[falter]

I recently bought a C4P from its original owner and afterwards he discovered a cache of tapes. He offered them to me for a nominal amount since i'd just bought the computer. Anyway, check out the stack!

https://drive.google.com/file/d/1pYQkQr ... sp=sharing

Here is a list so far:

Mindbender
Life
Lunar Lander
Craps
Archery Game
Airplane Demo
Guessing Game
Star Trek
Auto Wish Gen (?)
Label Maker
Line Editor
Renumberer
SCX-104 Sampler (OSI original)
Blackjack
Utility - Renumberer, GOSUB LBL, HEX-DEC, Sort-List, Screen Clear
Utility - Var TBL MKR, Disassembler, Sel. Scroll
GOBANG
Modem
Breakout
SCE-322 Math Blitz (OSI original)
Alien II
Dungeon Chase
SCE-313 Spelling Quiz (OSI original)
SCP-710 Kitchen Aid (OSI original)
Typing
SCG-900 Tiger Tank (OSI original)
Bomber
Electric Bill
Seawolfe
Crunched Othello
Personal Finance
Fast Screen Clear
Loan Calculations
O-107 Nautilus
O-Miner 2049er (?!?!)
Doodler
Stars
Garbage Collection
Chess

Naturally I'm going to digitize these.. I notice there aren't a lot of games posted on osiweb.. is that on purpose? Or am I missing them? If any of these are already digitized please let me know and it'll save some time. Hopefully they all work!

[stm]

Wonderful, good luck with digitizing the cassettes!

I had the chess game but I lost the tape, so I would love to play it once again...

[falter]

Getting back to this finally - I had intended to digitize the tapes once I checked them out and saw which were good or bad. Unfortunately my C4P had issues reading cassettes - I had a bad 3130 and a cut trace hampering that. Anyway, finally got it fixed and loaded up the first tape, Dungeon Chase by Orion. And it works! To my surprise, it's even color!

https://drive.google.com/open?id=1HjoIW ... p=drive_fs

The quality of the picture is not great - in real life it looks a bit better although the text has this weird 'barberpole' effect going on. I don't think OSI's color system was the best. My camera just couldn't sync with it well but the field of play is supposed to be purple, the main character yellow and so on. The screen updating is very slow.

I'm curious - is there any definitive list of OSI software, and then what has been digitized already? I don't see many tapes archived here. And also anything that mentions color vs black and white? I'm curious how many color titles were produced, since most OSI machines didn't usually produce color.

[bxdanny]

Systems that were sold as C4P and C8P systems always had color (and sound) built in; the earlier C2-4P and C2-8P systems generally didn't, although color and sound were available as options. No, OSI's color wasn't that good, and I think most people used monochrome monitors even with systems that had color output. The 540B board had RGB outputs in addition to color composite video, which I'm pretty sure would have produced a better color display, but those pins on the board generally were not connected.

One reason it was hard to sync the 540 color output to your camera may be that the vertical frequency is very non-standard, being 61.462 HZ by my calculations. But the horizontal frequency adhered very closely to the NTSC standard. While the 540B schematic shows a crystal frequency of 12.08 MHz, the actual crystal used was 12.083915 MHz. Divided by 768, that gives a horizontal frequency of 15,734.3 Hz, which matches the NTSC standard to the nearest 0.1 Hz. Is that kind of accuracy really needed? The schematic calls for an 11.79 MHz crystal when building a black-and-white board, which results in a vertical frequency of 59.967 Hz, or in between the 60.0 Hz of the original B&W NTSC spec and the 59.94 Hz of the color spec. But the horizontal frequency on such a board would be way off, at 15,351.6 Hz, which is why the horizontal hold control always had to be readjusted when switching one of those OSI-modified black-and-white TVs with composite video input between broadcast reception and video input from a C1P or C2-4P computer. (By switching I really mean connecting a cable to or disconnecting it from the composite input jack; there was no actual switch.) BTW, if anyone has an original 540B board built as B&W only, I'd be interested in what the actual frequency stamped on the crystal is. Is it exactly 11.79 MHz, or something else?

Dungeon Chase was a game written by Mike Cohen, who was also the author of DQ Secretary (and its WP6502-specific variant, File Clerk). A number of people (like Mike Cohen, myself, and Fred Beyer, the principal author of WP6502) wrote software for both DQFLS and Orion.

[Mark]

I've archived a few OSI cassette games here https://osi.marks-lab.com/software/games.html with screenshots running on WinOSI (it has an animated GIF capture). I've taken a few color pictures on a modern LCD TV connected to a C4P which seems to work pretty well too.

Yeah, generally I used a monochrome monitor on OSI 540 video especially for programming as the 64 column screen was pretty much unreadable on a color TV and OSI color bleed was bad. The barberpole effect can be altered using the color phase adjust potentiometer on the back of the C4P, but generally it only changes the speed of the effect, but never eliminates it completely.

I've been able to digitize a number of tapes and convert to them to binary using OSIKCS. There are other Kansas City Standard audio decoders that work well too. In general cassettes need to be sampled at a minimum of 22050 samples per second 8bits or better in a non-lossy format. (RAW WAV is fine, mpeg mp3 etc. will not work.) Volume levels should be as high as possible without severe clipping. OSIKCS can also be used to generate WAV files from binary, it speeds up playback 2% which is still compatible with real OSI hardware, but the resulting WAV file compresses very well with ZIP etc. usually taking 1/100th or less of the size of sampled WAVs.

Alternately, for a hardware only solution, I added a jumper to my OSI tape decoder to send decoded serial in to RS-232 out and I capture the raw serial data with a terminal program on another computer (ensure that the capture records RAW data including nulls).

I usually adjust the tape head azimuth/alignment slightly to produce the highest frequency or cleanest sound from the cassette player. (I have a cassette deck dedicated to playing random tapes.) There is usually a small hole on the cassette player next to the tape head for adjustment. Clean tape heads too for best results!

I look forward to seeing what you've found! Good Luck!

[dave]

Naturally I'm going to digitize these.. I notice there aren't a lot of games posted on osiweb.. is that on purpose? Or am I missing them? If any of these are already digitized please let me know and it'll save some time. Hopefully they all work!

There isn't a definitive list of OSI software, as far as I know. We do have catalogs from Aardvark, Orion, and others, plus the classified ads from Byte, etc.

The main reason there isn't a whole lot of cassette software archived is because only a small percentage of the OSI sotware library has been digitized and shared, and the OSI software library was always small compared to the bigger name machines of the day. While the scarcity of OSI software is due in part to OSI's smaller market share, I suspect that it is also in part because OSI didn't really do much to encourage software developers, and had very primitive tools. I suspect that OSI machines were more commonly selected by folks who wanted to tinker with hardware more than software, and that had an impact on the software ecosystem as well.

If you are able to digitize all these cassettes, it would be marvelous if you were to make them available to post on this site and Mark's site.