SPC Diskitjr

General discussions on the PCjr

SPC Diskitjr

Postby Brutman » Sun Jun 10, 2018 1:37 pm

This was a hard drive controller that I had seen advertised, but have never seen in the wild. I suspect they did not sell many of them ..

Anyway, I came across one recently. (It is a long story so I'll spare you.) The write-up and software for it is described at http://www.brutman.com/PCjr/pcjr_spc_diskitjr.html .

The short story - it's just an MFM controller. But it's nice to actually see one in person.
Brutman
Site Admin
 
Posts: 1078
Joined: Sat Jun 21, 2008 5:03 pm

Re: SPC Diskitjr

Postby Trixter » Sun Jun 10, 2018 2:40 pm

Thanks for the excellent write-up. Nice to see some discoveries can still be made this far out.
You're all insane and trying to steal my magic bag!
Trixter
 
Posts: 605
Joined: Mon Sep 01, 2008 12:00 am
Location: Illinois, USA

Re: SPC Diskitjr

Postby alanh » Mon Jun 11, 2018 5:27 am

Nice find! Thanks for sharing.

& only an IBM'r would 'think' about stuff. Others 'do' :)
alanh
 
Posts: 309
Joined: Tue May 10, 2011 6:52 pm
Location: Atlanta, GA

Re: SPC Diskitjr

Postby Brutman » Mon Jun 11, 2018 8:33 am

The conversation about the Diskitjr was kind of funny ... it's one of those items that is definitely R@RE! L@@K!, but that doesn't translate to expensive. I'd rather have a jrIDE a few times over.

There are a few other weirdo things floating around out there. I've never seen a Jr with the VGA sidecar (and the requisite hacks to enable it). There is a sound card sidecar out there too. The 8087 daughterboard would be interesting, but probably not hard to design from scratch. (/me starts daydreaming ... about having a EE degree.)
Brutman
Site Admin
 
Posts: 1078
Joined: Sat Jun 21, 2008 5:03 pm

Re: SPC Diskitjr

Postby alanh » Tue Jun 12, 2018 5:09 am

I think you'd need the 8088 running in maximum mode for the 8087, but I could be wrong. Not impossible but more than trivial.
alanh
 
Posts: 309
Joined: Tue May 10, 2011 6:52 pm
Location: Atlanta, GA

Re: SPC Diskitjr

Postby geoffdaddy » Thu Aug 09, 2018 9:18 am

Brutman wrote:The conversation about the Diskitjr was kind of funny ... it's one of those items that is definitely R@RE! L@@K!, but that doesn't translate to expensive. I'd rather have a jrIDE a few times over.

There are a few other weirdo things floating around out there. I've never seen a Jr with the VGA sidecar (and the requisite hacks to enable it). There is a sound card sidecar out there too. The 8087 daughterboard would be interesting, but probably not hard to design from scratch. (/me starts daydreaming ... about having a EE degree.)


Would a 286 accelerator be of more use than an 8087 add-on?
PCjr: 10MB RACore 01 hard drive expansion, Hotshot 640kB RAM expander, optical mouse, Xircom PE3, speech sidecar.
geoffdaddy
 
Posts: 131
Joined: Wed May 15, 2013 5:22 pm

Re: SPC Diskitjr

Postby Brutman » Thu Aug 09, 2018 9:29 am

Hard to say. There isn't much code that uses an 8087, so it's not a terribly useful option. A 286 accelerator on a PCjr is a nice gag, but if I wanted an AT I would have started with one. ;-0

Or put another way, at some point if you add enough options you don't have a PCjr .. you have a highly incompatible turbo XT clone ...

I think a tastefully modified PCjr has a NEC V20, a better keyboard, a jrIDE, maybe the ThinFont modification, a bi-directional parallel port (or two), and maybe an external 2nd floppy drive. The speed-up boards don't really appeal to me because they cost a bit of compatibility and I already have faster machines that fill those needs.
Brutman
Site Admin
 
Posts: 1078
Joined: Sat Jun 21, 2008 5:03 pm

Re: SPC Diskitjr

Postby OldComputerGuy » Fri Aug 10, 2018 1:36 am

Brutman wrote:Hard to say. There isn't much code that uses an 8087, so it's not a terribly useful option. A 286 accelerator on a PCjr is a nice gag, but if I wanted an AT I would have started with one. ;-0

Or put another way, at some point if you add enough options you don't have a PCjr .. you have a highly incompatible turbo XT clone ...

I think a tastefully modified PCjr has a NEC V20, a better keyboard, a jrIDE, maybe the ThinFont modification, a bi-directional parallel port (or two), and maybe an external 2nd floppy drive. The speed-up boards don't really appeal to me because they cost a bit of compatibility and I already have faster machines that fill those needs.


It isn't until you get into the Pentium era and the release of Quake that having an FPU meant something to most people. Before that, a few games would use it if you had it like Microsoft Flight Simulator, but it wasn't a hard requirement or the game wouldn't run without it. An FPU was primarily used by scientists and mathematicians who needed the extra precision and faster execution before then. It would just sit idle on the motherboard for the rest of us.
OldComputerGuy
 
Posts: 101
Joined: Sun Dec 04, 2016 7:28 pm

Re: SPC Diskitjr

Postby geoffdaddy » Mon Aug 13, 2018 7:45 am

Brutman wrote:Hard to say. There isn't much code that uses an 8087, so it's not a terribly useful option. A 286 accelerator on a PCjr is a nice gag, but if I wanted an AT I would have started with one. ;-0

Or put another way, at some point if you add enough options you don't have a PCjr .. you have a highly incompatible turbo XT clone ...

I think a tastefully modified PCjr has a NEC V20, a better keyboard, a jrIDE, maybe the ThinFont modification, a bi-directional parallel port (or two), and maybe an external 2nd floppy drive. The speed-up boards don't really appeal to me because they cost a bit of compatibility and I already have faster machines that fill those needs.


I hear ya. I keep trying to think of a hardware project I'd be interested in working on. My first love in the computer hobby realm is the Coleco ADAM, but I keep coming back to some existential arguments pro/con about such upgrades. If you change it too much then what's the point? I'd just get a modern machine and be done with it. :)
PCjr: 10MB RACore 01 hard drive expansion, Hotshot 640kB RAM expander, optical mouse, Xircom PE3, speech sidecar.
geoffdaddy
 
Posts: 131
Joined: Wed May 15, 2013 5:22 pm

Re: SPC Diskitjr

Postby Brutman » Mon Aug 13, 2018 8:40 am

Ah, the Adam .. I lost a lot of time playing Montezuma's Revenge on an Adam.

Now there is a very limited machine ...
Brutman
Site Admin
 
Posts: 1078
Joined: Sat Jun 21, 2008 5:03 pm

Next

Return to PCjr General Discussion

Who is online

Users browsing this forum: No registered users and 3 guests

cron