#hard drive
11 messages in this thread
A friend told me that you should never switch off or reboot your Amiga 2000
immediately after hard disk activity has occurred. Wait at least 20 seconds
after the last command has completed before rebooting etc. It has to do with
updating data structures on the hard disk from its internal buffers. This is
supposed to be similar to not taking a floppy disk out while the red light is
on. Is this a constraint of the AmigaDOS multitasking system?
I find it hard to believe that I would have to wait 20 seconds after exiting
WordPerfect just to turn off my hard drive.
-Pete-
Pete,
20 seconds is a long time to wait… and isn't necessary… about 3 seconds
after the last regular disk activity is plenty. That is about how long it
takes to 'flussh the buffers'. You can see it yourself… copy a file to the
HD, and watch the activity light. It will flash during the copy, stop, then
about 3 seconds later, flash again… after this last flash it's OK to reboot
or power off.
-larry
Larry,
On the 2090/HD combination…the 2nd flash 3 seconds later is the
auto-park.
Don
Don,
Well, it is if you select autopark as an option. It happens to be the
opportune time to park the drive, as that's when the buffers are flushed. If
you use TDebug on hddisk.device, you can actually see this happening. The
disk activity ceases, there is a pause, and then you get an UPDATE packet.
THe people that wrote the driver just decided to use that as a good time to
park. The flash will happen whether the drive parks or not.
Andy… if you're reading this, could you tell me if there's an entry in the
driver for 'park'? I would really like to write a couple of programs to park
the drive. One woul dpark it every 30 seconds or so, and the other would park
it on demand.
Speaking of that, any idea when the driver docs will be made available? i am
dying to write a backup program for SCSI quarter inch tape cartridges, and
need the 'pass the SCSI commands directly' methodology. I could do it from
the hardware specs in the tech ref manual, but prefer to 'keep it legal'.
-larry
Isn't that flash (after 3 seconds) just the drive parking? (Assuming a 2090
and a yes answer to auto-park).
Steve,
See my message to Don (#120475) for the scoop on autopark.
-larry
Thanks. That's good news. Waiting 20 seconds to turn off the Amiga sounded
yucky.
-pete-
5 seconds is enough for AmigaDOS to write the rootblock back to the hard disk
after the last disk write.
Connect a light to your harddisk. You'll feel better.
andy
Thanks for the info. 5 seconds is bearable, 20 seconds isn't.
-Pete-
If I am not mistaken, the quick blip of the drive is caused by the
disk-validator rewriting the BAM as it has changed now. I dont think it has
anything to do with parking the head. If you write to the harddrive and
warmboot before this little blip, you will notice that after mounting, the
validator must scan through the entire disk since the Bam is marked as
invalid at this point- this takes quite some time- that is why you must wait
for the second blip!!!
you are correct; its the root being rewritten; I think that the person who
mentioned parking the head was noting that that could also be an explanation,
if the auto-head park was selected in prep.
The 3 second wait isn't due to a scan of the disk, Btw…its a delay so that
if more disk io is started within that time, we don't have to bother
rewriting the root, and can just get started.
andy