New JR user.. Monitor, disk, DOS questions..

Hardware questions and modifications

Re: New JR user.. Monitor, disk, DOS questions..

Postby MikeModified » Sat Mar 07, 2015 8:59 pm

Nah. About the time I left, I sold my jr and bought an new XT clone with a huge 30meg hard drive. ;)

Mike
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Re: New JR user.. Monitor, disk, DOS questions..

Postby jmetal88 » Sun Mar 08, 2015 8:41 am

Sharkey1331 wrote:You were correct- the magic B drive config was using the cable that had a twist in it.. The box originally had an A drive (3.5", I think it's 720 kb flavor), and the cable (is this IDE?) was connected to that. Daisy chained off the same cable is the connector I used, with the twisty part in it. When I was originally trying to get the 5.25 to work, I simply plugged it in as I mentioned, and left the 3.5 connected and powered. Setting things in the BIOS, I noticed both drives going at the same time- so I unplugged power to the 3.5 early on. I'm guessing that, with the jumper moved in magic B config for 5.25, the A drive would have worked with the 3.5.. I don't have any discs for that drive either, so I just left it unplugged.

I moved the non-twisty connector to the 5.25, moved the jumper back to original (think this is position 0) and moved the 5.25 to A in the BIOS. No worky however.. I had to go back and move the jumper to the next position over as it was for magic B.. Now it is functional as A drive, and I can boot the computer this way. Interestingly, when it boots to DOS 3.20, it knows nothing about C drive, even though the BIOS is still configured for it. I don't know the history of DOS so well yet- is this because 3.20 wasn't a time when people had C:\ drives? I'm thinking this unlikely as the original IBM PC which predated the JR had a 10MB MFM in it (I think?)

I can still get my machine to boot from the HD by just opening the drive door on the 5.25 and booting. Then it comes up on the HD DOS version 6.22, but knows about the A: drive and also the D: CDROM drive, so I have a way to easily get files to the A: floppy from another, internet enabled modern PC. I might try to figure out more to the puzzle- it would be cool to have this 486 machine able to boot from floppy (DOS 3.20) and have at least the hard drive. I'm thinking the CDROM might be over the top with that old of a version of DOS. Also, I need to try to get the Xircom network interface going too. Forgot how fun these old machines were!!!

Jason


The DOS 6.22 partition is probably just too big for DOS 3.2 to recognize. The version of FAT supported by DOS 3.3 and below can't handle partition sizes larger than 32MB.
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Re: UPDATE: Working Drive! RE:New JR user.. Monitor, disk.

Postby jmetal88 » Sun Mar 08, 2015 9:13 am

Sharkey1331 wrote:For anyone that might be here that is only messing with these old computers because it is retro and edgy, but they were born with much newer machines being their first (Say, first computer was maybe a Pentium III, or some random XP box) this will seem absurd, but back in the day, there used to be some undefined amount of time needed to be spent when building a PC, where you'd just have to F$#@ with it to get it to work.


I get the sense that I'm probably the youngest person on this forum (I'm 26 years old at the moment). I guess I can't speak for other people in my age group, but I feel like people who think the setup process for a vintage computer is 'absurd' probably aren't actually going to get into it as a hobby. I guess they might join a forum if they find one in their grandpa's closet and it's not booting and they want to try getting it working to maybe see what's on it, but they probably won't stick with it if they find the process 'absurd'. The setup is actually the fun part, for me. My favorite part about any vintage computer system is when I get to set up new hardware or software on it.
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Re: New JR user.. Monitor, disk, DOS questions..

Postby Sharkey1331 » Sun Mar 08, 2015 10:55 am

jmetal88 wrote: The setup is actually the fun part, for me. My favorite part about any vintage computer system is when I get to set up new hardware or software on it.


Yes- see, you totally get it.. That wasn't a dig at younger generations by the way.. I was merely commenting on how today, things are all pretty much plug-and-play, and back in the day before that was the case, you actually had to dig in and figure it out.

Which is precisely why I am halfheartedly thinking about designing a kit computer (much like Vince Briel's Altair 8800micro, or replica one projects, but a bit different/more advanced, and not based on an existing platform per-se) I think that if there was a computer/kit design, taking things back to the old days of having to dig in and understand how things actually worked to make the computer do what you wanted it to do, it would be a great learning tool. I am currently designing/building a clone of the Briel Altair 8800micro to learn all of the things that I had not yet mastered in order to equip myself for my own computer design. The skills I've picked up so far: Understanding microcontrollers, how to program, implement, and use both Parallax's Propeller and also Atmel's AVR chips (ATmega8515 in this case.) I've got my clone running and have coded some assembly for it, and also I learned CadSoft Eagle pretty well so that I could make pro-looking PCB's for it. But, that is clearly taking this conversation off on a HUGE tangent. :-) I'll just say, I've been admiring all the board design work you and Alan have done on the JRide project- I know how much goes into it!

Back on target, I'm gonna keep my eyes peeled for a PC jr. monitor locally. What's the deal with these for folks that own them? After the 30 years since they were made, are you all finding you have to re-cap them? I love electronics, but don't really enjoy messing around the flyback section of CRTs- one of the reasons I like LCD panels so much! I saw one dude on this board actually re-capped his whole PCjr motherboard! Looked well done too. I would consider this, only I don't have a "pro" level de-soldering station, and think that any benefit of me doing this (even carefully) might be negated by the stress I put on the motherboard to recap it...
IBM PC Jr. NEWB! Parallel sidecar, Hotshot II (soon to be replaced with JRide)

Also, check out my clone of the Altair 8800micro Clone:
https://www.youtube.com/watch?v=y19zdzP ... yX5JoOO4qA
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Re: New JR user.. Monitor, disk, DOS questions..

Postby jmetal88 » Sun Mar 08, 2015 2:36 pm

Sharkey1331 wrote:Back on target, I'm gonna keep my eyes peeled for a PC jr. monitor locally. What's the deal with these for folks that own them? After the 30 years since they were made, are you all finding you have to re-cap them? I love electronics, but don't really enjoy messing around the flyback section of CRTs- one of the reasons I like LCD panels so much! I saw one dude on this board actually re-capped his whole PCjr motherboard! Looked well done too. I would consider this, only I don't have a "pro" level de-soldering station, and think that any benefit of me doing this (even carefully) might be negated by the stress I put on the motherboard to recap it...


Mine still seems to be going strong, and I doubt the guy who owned it before re-capped it since he just gave it to me. But they are getting to that kind of age, so I wouldn't be surprised if it has to happen soon.
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Re: New JR user.. Monitor, disk, DOS questions..

Postby geoffdaddy » Mon Mar 09, 2015 8:11 am

I personally use a CGA/Composite combination monitor. It's nice if you can swing one of those, since some older DOS games will output 16 colors on composite using the color artifact trick, otherwise it will appear as black and white on the CGA output. 7 Cities of Gold springs to mind.

I do have a PCjr monitor that I pull out of the box every now and then and it's nice to have for completeness. It works great, and I haven't had to touch the insides of it at all to recap or otherwise.
PCjr: 10MB RACore 01 hard drive expansion, Hotshot 640kB RAM expander, optical mouse, Xircom PE3, speech sidecar.
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Re: New JR user.. Monitor, disk, DOS questions..

Postby Sharkey1331 » Tue Mar 10, 2015 5:09 am

I remember back in the day, my family had a PC XT "turbo clone" that had a Amber monitor that was capable of CGA graphics, but appeared to have monochrome text? Its amazing to me how back in the day this stuff all seemed so normal and common place. Now a-days, I'm thinking what a crazy setup that was! I wonder if this was a type of combination monitor like you mention? I know it looked like monochrome, but I can remember playing Roadwar 2000 on it, so I know it did some level of graphics.
IBM PC Jr. NEWB! Parallel sidecar, Hotshot II (soon to be replaced with JRide)

Also, check out my clone of the Altair 8800micro Clone:
https://www.youtube.com/watch?v=y19zdzP ... yX5JoOO4qA
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Re: New JR user.. Monitor, disk, DOS questions..

Postby Sharkey1331 » Tue Mar 10, 2015 8:36 pm

Well, after some parts switcheroo, I now have 1 nice working, clean, and seemingly fully-functional PC jr. Unfortunately, I needed to take the 360kb drive back out of my "mothership" 486 to get the complete PC jr. Anyone got a working, 360kb floppy drive for sale?

Also, how do you go about making a floppy boot disk, if you do not already have the desired DOS version on your machine used to make the floppy? For example, the "mothership" has DOS 6.22.. I know I cold do a format /s to make a system disk, but that would result in a 6.22 system disk. Is there an easy way to manually make a system disk from a different version of either DOS, or windows?
IBM PC Jr. NEWB! Parallel sidecar, Hotshot II (soon to be replaced with JRide)

Also, check out my clone of the Altair 8800micro Clone:
https://www.youtube.com/watch?v=y19zdzP ... yX5JoOO4qA
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Re: New JR user.. Monitor, disk, DOS questions..

Postby jmetal88 » Tue Mar 10, 2015 8:56 pm

Sharkey1331 wrote:I remember back in the day, my family had a PC XT "turbo clone" that had a Amber monitor that was capable of CGA graphics, but appeared to have monochrome text? Its amazing to me how back in the day this stuff all seemed so normal and common place. Now a-days, I'm thinking what a crazy setup that was! I wonder if this was a type of combination monitor like you mention? I know it looked like monochrome, but I can remember playing Roadwar 2000 on it, so I know it did some level of graphics.


Eh, monochrome doesn't necessarily mean 'text-only'. It literally means 'one color', and there are various ways to build graphical screens with one color of phosphor available. When I was a kid, the CompuAdd machine my dad brought home from the office for me had an amber monitor with what I believe was Hercules graphics capability, which included the MDA text-only modes as well as sort of a CGA emulation, which reproduced the CGA graphics on a monochrome monitor by dithering the otherwise solid color. So it's very possible you just had a standard monochrome monitor used with a card that could emulate CGA.
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