Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!lll-winken!taco!hobbes!kdarling From: kdarling@hobbes.ncsu.edu (Kevin Darling) Newsgroups: comp.sys.m6809 Subject: Re: disk drives on color computer II Message-ID: <1991Mar22.122333.3689@ncsu.edu> Date: 22 Mar 91 12:23:33 GMT References: <1991Mar21.160021.23005@athena.mit.edu> Sender: news@ncsu.edu (USENET News System) Distribution: usa Organization: North Carolina State University Lines: 30 >1. I have some 360K drives from an old Leading Edge clone, they are >made by Toshiba, model # FDD5425A0N. There is a a 9 pin jumper block >on the drive (9 pairs of pins) labeled: > TM, L1, LD, HM, HD, D4, D3, D2, D1 >Does someone know what these pins do? The D4 to D1 pins are obviously >the drive selects but what are the other ones? A good guess would be: TM is to enable the termination resistors; do this for last drive on the cable. L1/LD control when the LED is lit; experiment to taste. HM/HD would be headload on motor/drive select (altho usually HD is called HS), but I'd set it for HM nevertheless: >2. I read somewhere (I think in an issue of the Rainbow) that the second >drive (/D1) should be set so the disk motor always spins even if /D0 is >selected. Is this correct and if so, why? For the same reason you'd want the head-load on motor select... all CoCo drivers _expect_ that if one drive is powered up and ready, then all are. If they actually aren't, you can get r/w errors without knowing it. Cause: the drivers will send step-pulses to the drive, expecting it to be ready. It's not because it's still spinning up, and so most or all of the step commands get ignored. Ouch, you read/write to the wrong track. >3. Has anybody ever ROMed OS-9 (I guess the kernal, the CMDS directory and >a BOOT file of some sort) and put the ROM in the COCO disk controller so >the machine boots to OS-9 like it currently does to the BASIC interpreter? A very few may have done that for L-I. Most people only have their ROM autoboot OS9 from disk on powerup, tho... as they often add new modules. best - kevin