gp2000

7 ms·

31.
by gp2000 11y ago
The partial workaround for negative G problems is a nice little story: https://en.wikipedia.org/wiki/Miss_Shilling%27s_orifice
32.
by gp2000 11y ago
I worked on the gcc back-end for TAOS. One requirement was a special output format called a "tool" which was like a single subroutine shared library. It was specified with the standard "-f" gcc extension syntax: "
33.
by gp2000 12y ago
I think because they were earlier machines the audience for the Model I/III/4 line is smaller. And no doubt many were sold to business which lessens the nostalgia. I've done some other Model III demos. Here's a good st
34.
by gp2000 12y ago
Yes. Conceptually the program is two threads. One reads from the floppy into a ring buffer and the other reads from the buffer and drives the audio and video. A few tracks are read to prime the buffer before the display thread runs in ea
35.
by gp2000 12y ago
I think the 4p has a Western Digital 1773 controller. I don't know if it is much better beyond supporting double density. My code does wait on status checks after writing commands. Maybe that's not necessary, but I haven't
36.
by gp2000 12y ago
Completely stock. The floppy drives can crank out a byte every 32 microseconds giving a theoretical maximum of 30.5 KB/second. Then you lose some to seeking and other overhead. A full screen is 1 KB so 30 FPS is within reach (I&#x27
37.
by gp2000 12y ago
You recall the disk capacity correctly -- 40 tracks, 18 sectors/track, 256 bytes/sector. However, uses track-at-a-time reads to squeeze 200 KB onto each disk. Track reads are a bit of a devil's bargain as certain data patter
38.
by gp2000 12y ago
With 320 x 200 resolution on the Grid Compass you might be able to use conventional techniques to convert from color to monochrome. At the 112 x 48 resolution I used, dither with or without error diffusion lost most of the image. Well, it
39.
by gp2000 12y ago
The program will try to read from the drive and pop up an error message. Or crash; the error checking isn't super robust. It would mean starting over at a minimum. The program isn't very user friendly, either. So for goodness s
40.
by gp2000 12y ago
It wasn't quite hot swapping as only one floppy can be active at a time. Still, even with a whole 7.76 seconds I was worried I would crack under the pressure.
41.
by gp2000 12y ago
Good analysis. It actually uses the 64 x 16 text mode which has semigraphics yielding a 128 x 48 display. I only use 112 x 48 due to floppy disk bandwidth limits. I'm thinking of trying the 40 x 24 text mode. The 80 x 96 resolution
42.
by gp2000 12y ago
Google of the past has severe doubts about Google of the present: ...we expect that advertising funded search engines will be inherently biased towards the advertisers and away from the needs of the consumers.
43.
by gp2000 12y ago
They were forced to change the name as they had lost the rights to use it: http://en.wikipedia.org/wiki/The_Source_(retailer) Briefly: international Radio Shack stores were put under control of InterTan, a Tandy spino
44.
by gp2000 13y ago
Not architecturally, but Federico Faggin and Masatoshi Shima were the key people on the 4004 and 8080 before leaving to form Zilog and build the Z-80. The Z-80 had to have DAA (decimal adjust) to be compatible with the 8080. Possibly the
45.
by gp2000 13y ago
Would love any and all analysis, but most interesting to me would be instruction details and especially the undocumented side effects. I'd also like to see comparison with the 8080 and how Zilog improved/changed the design.
46.
by gp2000 13y ago
I'd guess this goes back to the 4004 which was designed for a desktop calculator. Easy BCD really helps those applications so they must have had that in mind as a target market. There's not much point in using BCD once reasonabl