Mike's PCjr Page

Just wondering how popular was the PCjr with only 64kb RAM, and if anyone of you has one?
and is there a list of software that runs on that machine ?

thanks.

I have never seen one in the wild. I've seen a machine without a floppy from the factory, but never without the 64K memory expansion.

DOS required the 64k memory expansion. So it would be limited to whatever you can run on cartridges or load from cassette from within BASIC. (Either the cartridge or cassette version would work.)

so the PCjr 4860-004 didn't come with a floppy drive by default? I didn't know that. So it was almost useless. I wonder what was the target audience...

I bought my Jr with 128K & Floppy / Modem in ‘85

I was always under the impression that the 64K model with no floppy and only cart. was aimed at the classroom
arena to teach basic programming. Seemed a viable $$ value for this configuration and would be reliable as there
were no real parts to damage by the students, just turn it on and go....

I can't even imagine it in a school environment with just 64K and cartridge or cassette software only.

At best it would be a competitor to the basic model Commodore 64. Both would have cartridges. The PCjr would have a slight edge with more available RAM space left over compared to the C64, which had to fit the cartridge contents into the 64K address map. Both would be upgradable, but the PCjr would win that contest. (With a huge price tag ...)

Another use for the diskless PCjr was in classrooms using the Cluster sidecar. Then you'd have a remote boot solution that is low maintenance and fairly cheap without the expense of the floppy drives. But those would be 128K machines.

when I took assembly in college, we were using S-100 buss computers, Imsai 8080, with switches.
each class we had to re-enter the code by hand and run our programs, which we had to write on paper
before next class. Cart Basic would have been a dream hahaha...

Brutman wrote:I can't even imagine it in a school environment with just 64K and cartridge or cassette software only.

I think IBM was hoping a 64K PCjr would be an option for people who only want to program in BASIC and save/load to cassette, which was a valid use case for 8-bit home computers of the very early 1980s. Maybe it made sense in Feburary of 1982 when they started design, but seems silly in early 1984 when consumers finally got their hands on the systems.

I mean, cassette held on for longer in many parts of Europe, as I understand, so if they thought they could expand the PCjr into European markets, that may have been a factor, too?

The C64 cartridge space overlapping the 64k RAM space wouldn't have been that big of a problem, though, in that machine - bankswitching was always an option. (Granted, it meant you'd have to copy code into RAM, hand over to it, then bankswitch, do whatever you were doing, then bankswitch back to the cart, but...)

I am the original owner of a 64KB jr. I purchased it to use the motherboard after my 128 KB jr died one week after the warranty expired. I still have it in the box with the swapped-in bad motherboard. I still have the original good MB too.

mcsew2k wrote:I am the original owner of a 64KB jr. I purchased it to use the motherboard after my 128 KB jr died one week after the warranty expired. I still have it in the box with the swapped-in bad motherboard. I still have the original good MB too.

Just wondering, did it come with cartridges ? with which ones ? thanks.