skesterk@magnus.acs.ohio-state.edu (Shane Kesterke) (05/17/91)
Here's a simple question that I've never gotten a straight answer on in all the time I've been exposed to computers. When a floppy drive accesses the disk the budy light always stays on for about 2 seconds after it's done accessing. Is it safe to pull the disk out during this time or is it better just to wait till the busy light turns off? I know it's a dumb question, but like I said, I never got a straight answer for it in the past.
dj@ctron.com (DJ Delorie) (05/18/91)
In article <1991May17.152846.21839@magnus.acs.ohio-state.edu>, skesterk@magnus.acs.ohio-state.edu (Shane Kesterke) writes: > Here's a simple question that I've never gotten a straight answer on > in all the time I've been exposed to computers. When a floppy drive accesses > the disk the budy light always stays on for about 2 seconds after it's > done accessing. Is it safe to pull the disk out during this time or is > it better just to wait till the busy light turns off? Traditionally, this delay is a sort of "motor-on cache" in case you access the disk within a short period. It prevents having to wait for the disk motor to spin up each time you access the floppy. The BIOS simply sets a timer and shuts off the motor after a few seconds of inactivity. This implies that, once you get the command prompt back it's safe to remove the floppy, since the program has obviously finished writing to the diskette. HOWEVER, if you are running a disk cache program that does I/O in the background (you never can tell, either) it might just still be writing to the diskette. So if you have a disk cache and you don't know for sure if it does this, don't take the chance. DISCLAIMER: If you don't understand this explanation, don't remove the floppy until the light goes out. Same for your hard drive. DJ dj@ctron.com
david@kessner.denver.co.us (David Kessner) (05/18/91)
In article <1991May17.152846.21839@magnus.acs.ohio-state.edu> skesterk@magnus.acs.ohio-state.edu (Shane Kesterke) writes: >Here's a simple question that I've never gotten a straight answer on >in all the time I've been exposed to computers. When a floppy drive accesses >the disk the budy light always stays on for about 2 seconds after it's >done accessing. Is it safe to pull the disk out during this time or is >it better just to wait till the busy light turns off? > >I know it's a dumb question, but like I said, I never got a straight >answer for it in the past. The computer keeps the floppy spinning for several seconds after each disk access, just incase there is another floppy access. This way, the computer is not constantly turning the motor on and off, and waiting for the thing to spin up. Under normal conditions, you can remove the disk after the data has been written-- even if the thing is still spinning. I've done it thousands of times. However, things like disk caches will mess things up. Most caches have a "delayed write", where it just buffers the written data and writes it out when it gets a chance (while your program _thinks_ it's done). I would not reccomend taking the disk out early unless you are sure there is no cache. Also, often we tell 'normal' computer users to wait till the drive light is out simply because they cannot figure when it is "safe". These are the same users that call a 3.5" disk "hard" since it cannot be bent like the 5.25" "floppies". :) -- David Kessner - david@kessner.denver.co.us | 1135 Fairfax, Denver CO 80220 (303) 377-1801 (p.m.) | Reunite PANGEA! Why can't everyone have three or four line .sig's? |
gordon@osiris.cso.uiuc.edu (John Gordon) (05/18/91)
I think that it is because the "busy" light really indicates if
the disk is *spinning*, not necessarily being read/written. The drive
has to spin up to speed, do its read/write, then spin down and stop. The
light is on during all this process. I often take the floppy out after I
can hear that it is not being read/wrote, but before the light goes out,
and I've never had a problem.
---
John Gordon
Internet: gordon@osiris.cso.uiuc.edu #include <disclaimer.h>
gordon@cerl.cecer.army.mil #include <clever_saying.h>gordon@osiris.cso.uiuc.edu (John Gordon) (05/18/91)
>DISCLAIMER: If you don't understand this explanation, don't >remove the floppy until the light goes out. Same for your hard >drive. OK, I won't remove the platter until the light goes out. :-) John