Post by Gordon HigbiePost by RickPost by Gordon HigbieWe are using the IOMEGA 250MB ZIP ATAPI drive in an embedded system
with a customized device driver. When the FORMAT UNIT command (04H) is
sent to low level format a 100MB disk error code 8 is returned. This
operation works fine when 250MB disks are used.
Is anyone familiar with this problem?
Can somebody tell me what error code 8 means? IOMega does not release
technical information on this.
Gordon Higbie
Universal Avionics Systems Corporation
It's simple if you think outside of the customized scenario. You
cannot long format (low level) 100MB disks in a 250 drive. The 250
drive is incapable of doing so.
Thanks for the help, disk drive interfaces are new to me. Does this
mean that 100MB disks used in a 250MB drive must always be
pre-formatted?
Not normally. Part of it is that I don't know where you are getting
"unformatted" disks. If they truly have nothing but a factory "pre
format" with the servo tracks recorded but no FAT system then you
have to perform a long format (Iomega software) or what you are
referring to as a low level format.
The problem is that 100 disks in a 250 drive a pseudo compatible at
best. The 250 drive has to overwrite the wider tracks on a 100 disk
several times in order to fill out the entire track width and
maintain compatibility with 100 drives. Because of this there is no
practical way to format 100 disks in a 250 drive - which performs a
media surface check of the entire disk in the process. This is also
the reason why writes to a 100 disk in a 250 drive are painfully
slow.
Post by Gordon HigbieThe disks are available unformatted as well.
Not that I've ever seen. Retail disks have always had a DOS FAT16 or
Mac format and are labeled accordingly.
Post by Gordon HigbieOr maybe
"unformatted" means they are low level formatted but not high level
(file system) formatted?
What is the source for these particular disks?
Post by Gordon HigbieIf I don't perform the low level format and instead just make a new
file system on the disk then I am still able to read the old files
from the drive. If the disk is ejected and reinserted then the files
are gone. The drive apparently has a cache which is not getting
cleared after I make the new file system. Does anyone know how to
clear the cache?
Not knowing what this proprietary system/driver is you are using it
may not be the drives fault. Normally a "short format" with Iomega
software will wipe the FAT and that's pretty much it. But problems
with caches not being cleared are normally the fault of operating
systems like Win 9.x, not the drive itself. That's been a long
standing issue and you have to perform a "software eject" in Win 9.x
and up in order to flush any pending writes from the operating
system cashe. Doing a hardware eject from the drive itself will not
force Windows to finish writes from the cache, which can cause data
loss and can cause the previous FAT to be overwritten on a newly
inserted disk. The drives themselves do not have a hardware buffer
or cache system that delays writes to the disk.