Mike's PCjr Page

His books are great places to start.

Not sure how you came up with 71 colors? 16! = 16+15+14+13 etc. which gives 136 unique combinations. You might get better mileage out of the checkerboard effect in 640x200 4-color mode, as a real PCjr monitor has such a fuzzy dot pitch that the pixels effectively blend together. However, there's swi...

Always happy to see people experimenting with the PCjr. To be 100% accurate, it might be 16*16 combinations, but there are only 136 unique combinations of those. Also, some of the combinations flicker quite badly (ie. color #0 then #15, etc.). In practice, I found there were between 32 and 48 usable...

It's comforting that the speeds are now much closer to each other.

Curious how a CF card holds up under the same testing.

Using the RTC doesn't seem so bad as long as your minimum test reads/writes are over 30 seconds.

Is wear-leveling really a concern with this low frequency of IOs? Even old NOR-based cards are rated for 10,000 writes per block, and they perform wear-leveling so it's not dumping all the FAT writes into the same blocks. As a data point, I've been using the same 512MB CF card since 2004 (Silicon Va...

I somehow missed that the jrIDE used a memory window -- glad it does!

150KB/s writes and 250KB/s reads are actually a little above average for an 8088-based system. Unless you're using a controller that uses DMA or a memory window, that's very good performance. I grabbed 20 4G CF cards from an ebay lot for $30 a few years back. You can get an 8GB CF card on ebay for a...

Congrats on discovering the tiny, but passionate, PCjr demoscene :-) Because I'm roughly 75% of the "scene", I'm obviously biased, but hopefully there will be more productions for the PCjr from either me or others. The system has a lot of untapped potential (I'm not kidding, the fact that ...

I had a program on my FTP server that patched a DOS 5+ boot sector for you, using Mike's process, however it had a bug (nothing destructive) so I removed it. I put it back for you: Use an anonymous FTP client like filezilla to go to ftp.oldskool.org and cd to /pub/misc/Software/PCjr/ and download &q...