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Ti-990

Caldwelltech

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Aug 7, 2018
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My 1st post. I haven't had time to search much, so much info. I did do a search on TI-990's but didn't really come up with much. So, just curious if there is any interest in TI-990 parts pieces or even complete running systems? I have been working with them since 2002 and find myself with extra stuff but not sure if anyone likes to play with these.
I would also be happy to answer any questions anyone might have about these. I'm more in the hardware side of things and limited to the ones I work on, so don't know much about software, but may have some manuals laying around that could help.
 

commodorejohn

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I've always found them interesting on paper, but never had a chance to get hands-on with one :)

But for scoping out people's interest in actually acquiring hardware, it'd really help to know your general location - this stuff doesn't ship cheap.
 

durgadas311

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I've always had the same fascination, from the first time I saw a TMS9900 datasheet. Never had real hardware, but built a simulator a few years back. http://sims.durgadas.com/ti990/ti990.html

Unfortunately, I haven't been able to get it 100% functional. Certain OS images don't quite work right, and I have not yet been able to find the bug(s). Any chance you've got working 990/10 MMU hardware?
 

Caldwelltech

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What are you talking about? It's a mini computer. Haha. My back can attest to the size and weight of these old dinosaurs.
I am located in central Missouri, about 100 miles southeast of Kansas City.
What I have are TI-990 A13 chassis's, WD-800's, Mass storage II SCSI Brick hd's, a couple of FLEX scsi controller boards.
The systems I use are set up with: 990/12 SMI, 990/12 AU, 2Meg Memory (different boards, sometimes 1 meg, or 2 1 meg brds strapped together), CI403 Brds, and whatever controller needed (990/SCSI for bricks, TPBI for WD800's).
They run on DX10 3.7.0.
I also have 924+ keyboards and terminals, may still have a 931 terminal/keyboards. I do have one win 98 pc loaded with Mg931 emulator, and various manuals.
My Pop started a company in 76, and started using these systems some time in 80's. I was in the military. He died in a accident in 2002. I took over the company as my training was in electronics. By the time I started working at the company there was new PC based software. We still had/have few of these systems in use, so I maintain them. My knowledge of them isn't great other than keeping them working. I have one up and running as I type this.
Hope this helps, be happy to answer any other questions you might have, sounds like there might be some interest.
 

durgadas311

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The Rhode Island Computer Museum has two and spare boards, but we have never powered them on.

...

Thanks, I was thinking that a working/running 990/10 might be handy for me to test certain instructions to compare results against my simulator. But, on second thought, I'm not sure that's practical. I have another simulator that does work, so I can test any suspected instructions against that other simulator.

Still, I've learned a lot about how they programmed these machines, while tracing through all this code, and it truly was a different animal and is fascinating to see all the tricks that can be done.
 

jbdigriz

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Feb 18, 2007
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Programming manuals for the EI990 ethernet board and microcode programming manuals, espcially for the /12, would be very helpful for the simulator efforts going on with these machines. Anything else, docs or software, that you don't see already on bitsavers.org or the Internet Archive absolutely needs to be scanned in and submitted. Let me know if you need any help with that.

I use mostly Dave Pitts' simulator at present: https://www.cozx.com/ti990.html. DX10 and DNOS, but I also have a real /10, and S1500 (Unix), and a 990/1 aka 915 (TXDS). Looking for an FD1000 for that but probably will end up with an HxC type device.

If you want to part with any of those parts or say a whole /12, please do send me a private message. One last question, are you familiar with the TenX Cobol accelerator and do you know where one might be found? I have a manual but no board.

Regards,
jbdigriz
 

jbdigriz

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Actually I should have said "writable control store assembler and language" manuals or docs for the /12.

jbdigriz
 

Uniballer

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I worked for a company that used some 990 stuff in the early '80s. Kind of an odd duck. Much preferred DEC stuff at the time, and wound up helping them migrate to PDP-11s. The 990/12 I played with needed 3 phase power, ran dx10, had a DS50, 1600 bpi tape, and a fixed/removable disk cartridge drive (DS10?), and I don't know how many of those bizarre 911 VDTs. I stuck a 990/5 board on the TIline to handle synchronous serial communications. Two years of that stuff was plenty for me (really? 288 byte ADUs?).
 
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jbdigriz

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That's a use of the 990/5 board I wasn't aware of, but could be useful. Did the 3270 or 2780/3780 comm software support it?

Like to find a DS10 to replace the one I lost. Still have a small stack of disk cartridges. The DS50 packs I had are gone with the drive. Sigh.

An MT979 would be nice in case I run into any tapes. There is still a lot of 990 software that needs to be found and archived.

288 byte ADUs. Somewhat peculiar, but not unreasonable. DX10 seems to have been designed from the hardware up, not OS concepts down. I find it easy to understand once you grok that.

jbdigriz
 

jbdigriz

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Maybe when things get better, some of us can help you get them going again. Here's hoping, anyway.
 

jbdigriz

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"Maybe when things get better, some of us can help you get them going again. Here's hoping, anyway. "


Sorry, not sure how it happened, but it's not clear that I was replying to m_thompson here. Here's the relevant quote:

"The Rhode Island Computer Museum has two and spare boards, but we have never powered them on."
 

Uniballer

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That's a use of the 990/5 board I wasn't aware of, but could be useful. Did the 3270 or 2780/3780 comm software support it?
No. The company was building hundreds of units of custom equipment to be installed in a DOE facility in Tennessee, and UCCND wouldn't loan us one of their systems to talk to it. So I wrote custom software for debugging and production testing, including a DX10 driver.
 
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jbdigriz

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No. The company was building hundreds of units of custom equipment to be installed in a DOE facility in Tennessee, and UCCND wouldn't loan us one of their systems to talk to it. So I wrote custom software for debugging and production testing, including a DX10 driver.

Cool. Yeah, hard to get around custom software for custom hardware. I just wasn't sure if the 9903 port on 990/5 supported any kind of SNA. Thought about it and seemed to remember I had seen something to that effect somewhere but I can't find the reference right now.

Thanks,
jbdigriz
 

Uniballer

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As I recall, the data sheet for the TMS9903 (port3 on the 990/5) said that it supported both character synchronous (e.g. bi-sync) and bit-stuffing (e.g. SDLC) modes.
 

jbdigriz

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As I recall, the data sheet for the TMS9903 (port3 on the 990/5) said that it supported both character synchronous (e.g. bi-sync) and bit-stuffing (e.g. SDLC) modes.

That's what I'm seeing here. The only thing left that's unclear to me is which of the comms packages supported using that port in those modes. I'm almost certain DNOS DNCS did, not sure about DX10.

Thanks!
 

jbdigriz

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Feb 18, 2007
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Currently, I'm corresponding with a /12 owner with a dead power supply who's looking for a schematic for the PS PWB. It's different from the one in my 40A A13, so, 2 things:

1) What other versions of the A13 are there? The 1980 990 Maintenance Drawing set and the /10 Hardware Reference on bitsavers only show a 20A and the 40A chassis. I'm thinking I've seen a reference to a 60A A13 that may be what my /12 guy (not sure if he's here or not) has. Can anyone confirm?

2) If anyone has a copy of the /12 hardware ref and/or a later drawing set that they've scanned in and posted somewhere, please post a link. I've already contacted CaldwellTech privately, waiting for him to get a chance to see if he has a copy, but if anyone else has one they'd be willing to lend out for scanning, please PM.

Thanks,
jbdigriz
 

ict

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I always wanted a 990 but didn't get a chance at one until recently when I lucked into a Business System 300, which seems to be basically a 990/10A with an integrated disk controller built into a terminal enclosure. It came with no peripherals, of course, so now I'm hunting for a keyboard and a WD500 or WD800 mass storage system as well as any documentation/software I can find. The system looks to be maxed out to 512K memory and with all optional I/O, and even more interestingly has a "PBIC" card in place of the usual 2/4-port terminal card they were offered with, it seems like it might be some sort of CRU buffer card to allow the machine to interface to an external expansion chassis, but I've never found any mention of it anywhere as an option.

Other than the hardware, if anyone has any information or even just commentary on these machines I'd love to hear about it! They seem like a killer system for a space-constrained mini enthusiast, but there isn't much out there on them aside from a couple documents on Bitsavers and some product announcements in InfoWorld/Computerworld and the like.
 

deramp5113

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I worked on 990 system in 1981/82 in a multi-user environment. The the main thing I remember was the unique way user terminals were handled. Instead of bidirectional serial communication as with most terminals, video was generated for each user in the 990 chassis and video cables ran to each terminal. Keystrokes from the keyboard were returned to the 990 over the video cable using DC/baseband.

Mike
 

commodorejohn

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The the main thing I remember was the unique way user terminals were handled. Instead of bidirectional serial communication as with most terminals, video was generated for each user in the 990 chassis and video cables ran to each terminal.
Well that makes me really curious. Doesn't seem conducive to a particularly high refresh rate...
 
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