krieg@jupiter.uucp (Andrew Krieg) (01/15/90)
I have had this weird quirk in my ST system ever since I got it (3 years ago) and I am wondering if it is normal. I have a 520 ST, a single sided disk and a double sided disk. The double sided disk is drive A and the single sided disk is drive B. Whenever I access drive A, drive B spins also. Should this be? Is this harmful? The drive light on B does not come on, but if I have a disk in there, I can hear it spinning. If I access drive B, drive A does not spin. Anyone know what is going on? -- ========================================================================= = Andrew Krieg The Marvel Historian = = G.E. Medical Systems - CT - New Berlin, WI = = USENET: krieg@jupiter.med.ge.com = ========================================================================= = "Holy one track Batcomputer mind!" - Robin = =========================================================================
matthews@umd5.umd.edu (Mike Matthews) (01/15/90)
In article <1871@mrsvr.UUCP> krieg@jupiter.UUCP (Andrew Krieg) writes: >I have had this weird quirk in my ST system ever since I got it (3 years ago) >and I am wondering if it is normal. I have a 520 ST, a single sided disk and It is. >a double sided disk. The double sided disk is drive A and the single sided >disk is drive B. Whenever I access drive A, drive B spins also. Should this >be? Is this harmful? The drive light on B does not come on, but if I have a >disk in there, I can hear it spinning. If I access drive B, drive A does not >spin. Anyone know what is going on? > >= Andrew Krieg The Marvel Historian = Nothing to worry about; that's what they all do. Why, I don't know. Mike
hyc@math.lsa.umich.edu (Howard Chu) (01/17/90)
In article <5948@umd5.umd.edu> matthews@umd5.umd.edu (Mike Matthews) writes: >In article <1871@mrsvr.UUCP> krieg@jupiter.UUCP (Andrew Krieg) writes: >>I have had this weird quirk in my ST system ever since I got it (3 years ago) >>and I am wondering if it is normal. I have a 520 ST, a single sided disk and > >It is. More elaborately... There's only one set of data and control lines that go to both disk drives. A particular drive is chosen by the proper number (0 or 1) appearing on the drive select lines. (The controller is capable of addressing 4 floppies, but there are only enough lines on the ST interface to address 2. Oh well.) In any case, the Motor On command gets fed to both drives, so both will start spinning. However, since only one drive's "select" signal will ever be active at a time, the other drive sits there, the light doesn't come on, it doesn't respond to other commands, etc... -- -=- PrayerMail: Send 100Mbits to holyghost@father.son[127.0.0.1] and You Too can have a Personal Electronic Relationship with God!