A computer built by IBM that was not 100% IBM compatible. Most games that advertised themselves as "IBM compatible" would fail miserably on a PCjr.
Optional peripherals included a real (non-chiclet style) keyboard, 5.25" floppy drives, a tape drive (they provided the cable, you have to provide a tape player), a CGA color monitor, and a memory sidecar. The PCjr also had slots for ROM cartridges. Some games, a BASIC interpreter, and BIOS hacks (a new system font, caps lock indicator lights, etc) came on cartridges instead of disks. PCjr peripheral ports were non-standard (read: only IBM accessories would plug in), so newer hardware couldn't connect to a PCjr without an expensive adapter. The power supply was half in the case, and half in a black brick-sized transformer that sat on the floor behind the desk. Adding a second floppy drive required adding on an expansion chassis on top of the original case, complete with its own power supply, cord, and brick transformer.
I have one of these beasts, stuffed in the back of a closet somewhere. It still works, chugging along at a glacial 4.77MHz, with a whopping 512kB of RAM. (That's upgraded from the original 128kB.)
Perhaps I've been too harsh on the old PCjr. It was an amazing leap forward from the original IBM PC
. The thing that really set it apart from newer computers I've had was the sound. The PCjr had a 3 voice synth, that could do square
, or sawtooth
(triangle) waveforms or white noise. The BASIC
cartridge included "play
" and "noise" statements that used all 3 channels. One of my first forays into programming was teaching that machine to play Minuet in G
. Somewhere in my piles of old 5.25" floppy disks
, I have a basic program that plays the entire 3rd movement of the Moonlight sonata
. Whoever programmed that must have had the patience of a saint
. I should haul mine out of storage sometime, just to play Beethoven
on it. I know there are emulators
, but they just don't sound the same as the old analog
oscillators in that synth chip.