AJB%DLVH.DARESBURY.AC.UK@cornellc.cit.cornell.edu (06/14/90)
Although this is perhaps not quite the forum for hardware observations/ features as a MINIX devotee I think ST subscribers may be interested in the following info. 1) MINIX defaults to a white-on-black display. This can tend to underdrive the high-res SM125 b&w monitor. The symptom of this is the display fading and the need to increase the brightness level. The reason is that, under low drive, the CRT cathode wanders from its optimum 70V to 80V. The condition can be rectified(!) by putting a 70V zener on the cathode. 2) A recent experience was upgrading from a 1040ST to a 520STE(2Mb). I went through 2 machines which, after 3-6hrs, both started to write garbage over my MINIX partitions (also occurred under TOS). Lots of 'fixes' were tried (including changing the DMA buffers with the faster AS and ALS type chips; also using no DMA buffering at all) to no avail. It turned out that the DMA chip is near the end of a power distribution grid in the STE and raising the PSU output (slightly!) cured the problem EVEN THOUGH THE DMA VOLTAGE WAS ABOVE THE SUPPOSED TTL MINIMUM ACCEPTABLE VOLTAGE OF 4.75V. (don't raise the voltage above 5.2V at the PSU end) Incidentally, I run MINIX with an ICD host adapter and call the STCLOCK routine from within RC to read the time at boot-up. Please could the 'SUPRA/ICD CLOCK RETURNS...' message be removed from the kernel in the next release; hexadecimal-encoded times are not that meaningful and don't inspire me to calculate the time when, after logging on, I can just type 'date' anyway. Alan Bleasby