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Breathing new life into 1981 IBM 5150

Chuck(G) said:
When DOS 2.0 came out with the ability to load device drivers, my 5150 got a hard drive--a SA1002 8" drive connected to a WD1001 controller, hitched to a small ISA card I made (still have it) in the 5150. Boot from floppy, load the driver and you're good to go with a glorious 4MB of disk. My 5150 was modified with the Purple Computing mezzanine board to a whopping 256KB. (still have the docs for that one).
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So you are saying the early 5150 can load drivers from floppy. But what about card bios? My VGA card just will not display video.. And the XTIDE can be loaded from floppy driver as well?
 
Well, the drivers have to be created as loadable by DOS; those aren't the same as the BIOS ROM ones. For my hard disk, the driver was my own creation. I suppose it might be possible to encapsulate a VGA BIOS in a TSR or loadable driver and activate it after loading. Never tried it though.
 
You wouldn't need to load anything for VGA. The VGA BIOS is mapped, the PC BIOS just doesn't scan for it and so it never get called. It would be a matter of using DEBUG to execute the VGA BIOS, just like you do with hard disk controllers when wanting to execute the LLF routines.

But the question is: why all the fuss? If you add VGA, you are way off from period correct anyway. So just go with the 1982 PC BIOS.
 
That would be something. Waiting for video to kick on after a complete post. I was just curious. I have no intention of using a VGA card on this thing. I only want to use it now as I have a VGA monitor on the bench and not an RGB/MDA.
So XTIDE can be loaded from floppy as well?
 
So this 5150 is causing me to work on all my 5150s and my 5160... My 5160 for instance has a double-height 5.25" SCSI 2GB hard drive. So I need to blank the whole side. HAve two sets of vent holes and leds wont look great.

3D print is an option but it will never look perfect.. I know im nitpiking.
 
The originals are pretty rare, but I recall seeing some stuff on thingiverse that could work.

I’ve only got one full height blank, in my 5161, and it’s just a plastic plate with some clips on the back. Looks like the photos here: http://minuszerodegrees.net/5150/dcp/5150_disk_cover_plate.htm

The half height are a little more common, in my limited experience, but I think were only in the later XT with a half height drive. It’s basically a metal box that attaches to the bottom of a drive.
 
I wish there was a 3D printout of that large blank Jafir... Like I said I need it for one side with a large hard drive. I need the half height for the right side since I only have one 3.5" 1.44MB drive in a tray adapter.
 
I have seen 3D printouts of the large black cover but with small cutouts for various devices. I am certain that there is on either completely blank cover or with small vent holes and a LED hole. Skipping the cutouts doesn't seem that difficult. The results for the 3D searches are poorly organized and I certainly won't look through 2,0000 pages of results to find an exact match.

In good news, there are a number of 3D printed external 5.25" enclosures. Perfect if the idea of adding external floppy drives ever appeals.
 
There are some photos on mzd at that link I shared earlier. Looks like a big metal plate and some clips. I can dig mine out later and see if it's the same.
 
There were some hdd solutions for dos 1 on the early bioses but I think they either required a boot disk with a modded dos, or some emulated a floppy. Read about one system that split the hdd into multiple floppys and had tools to switch to them.

There were also lots of 'floppy emulators' As far as i can tell these are hardware ram drives. Would like to get my hands on one of these as well as one of the early hdd systems.

There were also ads for upgrade quad density drives, not sure how dos got on with them.

It's your system so it's up to you how you proceed but if it were mine (and I had the other later 5150s), I would try to trick it out with an external HDD within the confines of the first rev BIOS. Ideally with an original solution, but i guess you could always brew your own.

Emulating the floppy seems to be the place to start. I think smbaker or smbarker made a card that could emulate a floppy controller. His you could load disk images via a network. So that should work, but it could be made much simpler by responding to the correct I/O address and store a 160K floppy in an EPROM. Would this work? Is this a relatively simple card to make.
 
Multiple floppies? Are you thinking of the original Corvus/IMI hard disk for the Apple?
I do recall that the OEM edition of DOS 1.x allowed for incorporation of hard disk drives (much like CP/M did). Of course, you were limited to FAT12 restrictions.
 
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