gjwelych@SUNRISE.ACS.SYR.EDU ("Welych, Gregory J.") (12/21/87)
Hi all.... I have had one of my disk drives die on me, and rather than try to get it fixed, (it was only a single sided drive anyways) I decided to buy a cheap(er?) double sided drive. I hooked the new drive into the little converter card inside an Atari drive, and connected the power supply up. It works fine except for one slight problem which can cause MAJOR problems with certain software. The problem is this: Say I boot up with disk A in drive A, and disk B in drive B. ( drive B is the new drive ) Then after I get the desktop, I change drive B's disk to disk C. ( I have a window automatically opened for drive B on the desktop) Then I hit ESC to get the new directory, but it doesn't know I changed the disk. I am assuming that the disk drive has not reported media change to the ST so it doen't think that there might have been a switch. Now to my main question: What in the Atari drives senses the change of media?????????!!???? And how does the drive signal this to the ST????? Thanks in advance for any help, Greg Welych. Internet: gjwelych@sunrise.acs.syr.edu BITNET : GJWELYCH@SUNRISE -----------\____ NOTE: same machine Internet: gjwelych@amax.npac.syr.edu ------
apratt@atari.UUCP (Allan Pratt) (12/23/87)
in article <8712211937.AA01474@ucbvax.Berkeley.EDU>, gjwelych@SUNRISE.ACS.SYR.EDU ("Welych, Gregory J.") says: > What in the Atari drives senses the change of media? > And how does the drive signal this to the ST? The media-change sensing is done using the write-protect signal from the drive. The assumption is that when you take a write-enabled disk out of the drive, the write-protect sensor will pop up, and the drive will signal "write protect" to the controller. When you put another disk (or even the same disk) in the drive, the write-protect sensor will be pushed down again and signal "not write protect." When a disk is really write protected, of course, there will be no transition on the line. Because of this, write-protected disks go into the "maybe changed" state 1 sec (I think) after the last disk access. (The assumption is that you won't change from one write protected disk to another within one second). When a disk is in the "maybe changed" state, the next access (through RWABS or maybe Floprd) will check the serial number of the disk in the drive. If it hasn't changed, then the disk hasn't changed, either. This is another assupmtion: you should not have two disks with the same serial number. If your drive suppresses write protect changes when there is no disk present, then switching from one write-enabled disk to another will not cause the transition, and the BIOS will not sense media change. Sorry. Nobody said it would be easy. ============================================ Opinions expressed above do not necessarily -- Allan Pratt, Atari Corp. reflect those of Atari Corp. or anyone else. ...ames!atari!apratt
ljdickey@water.waterloo.edu (Lee Dickey) (12/29/87)
Thank you, Alan, for the informative answer, which raises another question... In article <914@atari.UUCP> apratt@atari.UUCP (Allan Pratt) writes: > >The media-change sensing is done using the write-protect signal from the >drive. ... > >When a disk is in the "maybe changed" state, the next access (through >RWABS or maybe Floprd) will check the serial number of the disk in the >drive. If it hasn't changed, then the disk hasn't changed, either. >This is another assupmtion: you should not have two disks with the same >serial number. > ... What is the "serial number" you mention? I have seen no mention of it before. I have noticed something called "disk label" that comes up when I ask it to "SHOW INFO". Is *that* the "serial number"? How can I be sure that no two disks have the same serial number? -- L. J. Dickey, Faculty of Mathematics, University of Waterloo. ljdickey@watmath.UUCP UUCP: ...!uunet!watmath!ljdickey ljdickey%water@waterloo.edu ljdickey@watdcs.BITNET ljdickey%water%waterloo.csnet@csnet-relay.ARPA