DOS 2.1 On Cartridge?

[Tempest]

Has anyone seen this before? It's DOS 2.1 on a PCjr cartridge.

http://atariage.com/forums/topic/263021 ... try3712917

[Trixter]

Wow, never seen that before. Makes sense to have though, you'd never need a boot floppy.

[Vorticon]

Can this cart be replicated? Could a later version of DOS work as well in that format?

--Walid

[usotsuki]

DOS 3.00's boot files (ibmbio.com, ibmdos.com, command.com) are about 59K. Between the overhead of a filesystem and an INT13 driver, I'm not sure you could fit even that in 64K - you'd need bankswitching hardware.

[Trixter]

It is possible if DOS doesn't need to RUN out of the cartridge; you could store it compressed, then decompress it into ram as if you were loading it from disk. However, running off the cartridge is the real benefit, because that frees up more memory to run programs (something important for a system that steals from system memory for its video buffers).

[Tempest]

He posted pictures of the chips. They're regular ROMs, not EPROMs like I was expecting. This just gets stranger and stranger.

[alanh]

He posted pictures of the chips. They're regular ROMs, not EPROMs like I was expecting. This just gets stranger and stranger.

Why is that strange? I wouldn't expect to UV erase them in the field.

[Tempest]

I mean I thought this was a prototype of sorts. A one off that maybe the internal IBM people used or something. I didn't think this was actually a production cart.

[Meknapp]

It would be awesome to get a dump of this cart!

[OldComputerGuy]

How big is the cartridge space in memory?