CompuServe Messages

John, Well…let's do a little math: low-res screen is 320×200 pixels. That'd be 64000 bits or dividing by 8 for bytes…that gets us 8000 bytes per frame. Presuming full frame animation, at 60 frames per second…that be 60×8000 for a low-res, 2 color, full frame animation needed or 480,000 bytes per second off the drive. Of course, that's sustained bytes per second, not burst rates. That also presumes that the full frame needs to be loaded everytime…not just the changed pieces. 4 colors would take 2 bit planes, or twice as much data, 8 colors would take 3 bit planes or 3 times the data (1,440,000 bytes per sec). But let's stick with the data needed per frame. 8000 bytes every 60th of a frame for 1 bit plane, 16,000 per second for 2 bit planes (4 color) and 24,000 bytes per frame for 3 bit planes (8 color). Now, a hard drive spins at 3600 revs per minute, or 60 revs per second. That works out well for us, because we have 60 frames per second, and a drive that spins 60 times a second. Thus…the amount of data we can get off the drive in one revolution would be the absolute maximum we can display in one frame. Since almost all Hard drives can only read one head at a time, then it makes no difference how many heads it has…it can only read one at a time. Thus it comes down to how many sectors per track are available. Presuming 512 bytes per sector, if the drive has 26 sectors per track (a "normal" figure)…you can read 13,312 bytes every 60th of a second. If you get a higher density drive, one that has 35 sectors per track…you can read 17,920 bytes every 60th of a second. Thus…the maximum you can get at 60fps would be a low-res 4 color full frame animation. This presumes very little, if any, head movement is required to read the data. Don