toms@oakhill.UUCP (Thomas Spohrer) (02/06/90)
In response to my posting of the following message: > I have an original IBM-PC with an after-factory Western Digital >controller and a CMI 20MB hard disk. When I purchased it I had a >real need for the HD but due to $$$ constraints I bought the cheapest >one I could find (read: ITS NOISY!). Now I rarely need the harddisk because >the computer is mainly used as a terminal and for light word processing. >What would be ideal would be a separate power switch on the HD such >that it did not need to be spinning when its not being used. > > Question: Is it OK to simply put a toggle switch on the +12 volt > line to the disk but not make any changes to the logic > power to the disk or controller ? (It would be acceptable > to have to reboot to enable the HD again). As usual I got many more people interested in the answers to this question than I got answers ! Again, I would like to here from anyone who has any information to add to this discussion. It may have not been clear that my plan is to NEVER turn on the hard disk while the computer is already running--That is, if the hard disk is needed it is enabled before the computer power is turned on, the rest of the time the computer is turned on and off while the hard disk is not powered. The following are the only responses that I got answering the question: ============================================================================== The experience of most places with lots of hard disks indicates that the power off time is >24 hours for best life. That is, if the drive will be unused for >24 hours, power down. If less leave it up. One of the guys in the computer repair section kept a log of the practices of people with failures and concluded that systems should be on overnight, off over the weekend. This was true for disks, monitors, and silicon. Your milage may vary, but I personally would leave power on. If the noise bothers you by a cheap radio or but the system on the floor... --- bill davidsen (davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen) ============================================================================== NO You might trip out your power supply that way, or even screw it up altogether. And that's only the good news.. Even my quiet HD can get irritating at 3 a.m., I wish it *was* safe! Dave E. (moncam!acorn!ukc!mcsun!sunic!uupsi!rpi) ============================================================================== It seems that if you were to "switch on" the HDisk while the system was running, you might glitch the +5V/+12V output from the supply to the rest of the system as the disk powered up and drew a lot of current. I don't know if this "glitch" would be bad enought cause problems at your cpu. Fernando Botelho AT&T Bell Labs - Naperville, IL [{your favorite backbone}]...att!iwtil!fmb ============================================================================== . . . . I would be a little leary about just cutting the 12 & 5 volt power - what about the voltages on the data lines - what effect on the HD electronics (in the drive, not the card) would they have, if no "real" power is around??? |James Cayz can be found via: USPS: Educational Technology Laboratory, |E-MAIL (ARPA): cayz@louie.udel.edu : 203 Willard Hall Education Building, | : University of Delaware, Newark DE 19716 ============================================================================== -- =========================================================================== Thomas Spohrer UUCP: {harvard,utah-cs,gatech}!cs.utexas.edu!oakhill!toms ===========================================================================