Installing 70's Software, How Hard Can It Be?

Today, we're going to get some software going on the Sol 20! From the internet! How hard can it be?

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#Sol20 #8080 #70s

[dwreid]

I'm digging way back in my memory but the problem you are seeing with expansion RAM may be due to address space. The Processor Tech Sol 20 used an 8080A and only had 64K of address space. The personality module and 1K of SRAM occupy the top 16K window of address space. That means you ONLY can add 48K or RAM to the S100 buss before it overlaps the personality module and onboard RAM. To work correctly, you need either a smaller RAM board (16K for example) or you need to disable the top 16K of RAM on the 64K RAM board.

It's been a long time since I owned one of these but I think that might solve your problem.

Good luck.

OH.. and yes. That was the game of life. NOTE: A few of the one person shooter games included sound effects, even though the SOL-20 did not have a sound card. To make those work, you sit an AM radio next to the computer and tune it to the low end until you can hear the sound effects. (there will also be no small amount of ambient noise mixed in) But... it works. I wish i better remembered the frequency to tune the radio to. It's rather finicky so you have to play with it a bit. One of these games was the game of TARGET (TARG). You will find the game code and manual in the GamePack on the SOL20.ORG site.

Processor Technology sold expansion cards for S100 machines other than their own so don't let that fool you. This 64K card was probably never intended for use in this computer.

[DystopianOverture]

I love how the retro computer community has gone from being 'ooh lets look at the games' to 'can we use google with them'. The never ending tinkering is so interesting to me.

[suddenlyvlogs]

Definitely thought you said ADHD powerhouse, not 8080 powerhouse.

I’ve never felt so seen 🤣🤣🤣

[mediocrefunkybeat]

I'm so glad that RTFM still applies to a 47 year-old machine!

[esra_erimez]

Awesome video. My dad said that even when those machines were new, they were very temperamental

[krissjacobsen]

Oh yeah! Was waiting for my weekly dose of totally normal computing!

[cstacy]

The LOCAL key is so that you can type at the machine while it is in terminal mode. In the old days of teletypes, this is for doing things like punching the paper tape with some extra content in the middle of a session (without transmitting that content to the remote end). In the era of a smart terminal or a terminal program, it might actually be for entering terminal program commands.

[charles_xcx]

Now THIS is why I'm such a fan of this channel. Nothing quite like learning about a new computer one week and trying to exploit it the next

[ExtraordinaryBen]

Back around 2010 I picked up a Sol -20 from my community college in a surplus sale for $5. it needed keypads and the display was slightly corrupt, but I flipped it for almost $2k on ebay as-is. Kinda wish I kept it, but it was great financial help getting through college.

[Francois_L_]

Computers like that really make you appreciate an Apple ][ or a VIC-20.

[ncot_tech]

Have to say, when shopping for a computer I do tend to pick the ones that have that essential "Screen and Keyboard" upgrade. Sure beats your traditional LEDs and front panel switches. 😁

[soupwizard]

8:29 I'm surprised the USB to RS-422/485 serial adapter worked at all, since afaik the SOL-20 has a RS-232 serial port.

[Jaxermd]

Would love to see a Lisa 2 with upgrades and running MacWorks MacOS. Maybe get ahold of a twiggy drive.

[michaelcloutier]

You need to source a drive controller and add a GoTek Floppy Drive Emulator. DO IT!

[lukezaa]

That was funny. One one creators just said to you. RTFM XD

[megaflops]

Uploaded 53 seconds ago? *immediately clicking it*

[MNGoldenEagle]

I wonder if the memory card you were using was working properly but was configured to map its RAM over a conflicting area of the memory space. If it's overlapping with hardware registers, then it wouldn't surprise me if that would cause unusual behavior, especially if the memory card is refreshing the RAM using writes.

[voidstar]

Great lessons learned about the LOCAL key and SPEED throttle. Congrats on first steps in getting any software into the system. On the last page of the SOL-20 manual, IIRC there was a price list of all the various accessories (which quickly got very expensive, $3000+ in '75 for a functional system with data storage, 4K+ RAM).

[Mike_Neukam]

When you read from address 0, you received a page full of FF. That implies the memory isn't outputting to the bus at area. There may be a problem with the chip select logic or a bus transceiver. Also be aware the the S100 "standard" was more of a guideline. Ram and rom cards sometimes need configuration or modification beyond just addressing to work properly with a particular system. You'll need to reference the documentation for both the ram card and the Sol to understand how it needs to be configured to handle memory reads and writes.

The S100 bus came from the Altair which had a full front panel that handles memory reads and writes. When later systems stopped including the full featured front panel, memory read and write circuitry changed and was not always done the same way across different systems. Add in shadow memory and bank switching possibilities and you end up with a lot of different ways that a memory card can be configured. If that single card has a full 64k of RAM, I'd suspect it was made pretty late in the s100 era. There are likely a number of different ways it could be configured to meet the needs of the system it's installed in. If it wasn't originally installed in a SOL20, there's a good chance that it's not configured correctly for the system.

Also remember that the 8080 can only address 64k of memory. The internal ROM and RAM shouldn't be allowed to occupy the same address space as the expansion RAM at the same time. You'll need to disable the ram on the expansion card so that it doesn't overlap the internal RAM and ROM.

[mutestingray]

Someone needs to run a Windows activation script lol