SCSI first disk

stevel stevel at
Mon May 28 00:24:43 AEST 1990

jimmy at (Jim Gottlieb) writes:

>Common net wisdom seems to indicate that it is best to use a non-SCSI
>drive as the first disk drive.   Is there a safe way around this?  I
>would rather not use up slots for both an ESDI and a SCSI controller.

Not True! I have only one disk on my system and it is a
SCSI. There are people out there with several SCSI disks on one
controller. 386/ix supports up to four drives on one SCSI controller.
It assumes that tape drives take up another couple of LUNs and itself
takes yet another.

People who have had trouble configuring thier systems have been using
NON-SCSI drives as 0 and 1 and then trying to put the SCSI in as drive
3 or higher. This requires getting /etc/partitions to be just right.
I've never tried this so I can not give any advice on getting it
right, but make sure you do the mkpart commands carefully.

My advice is go for a SCSI only system. If you want real tape backup
then you will not have to get another controller. The super fast disk
transfer times of IDE or ESDI disks are outwieghed 3 to 1 by seek
times. On top of that is the file system overhead is the limiting
factor for a disk any faster than 15 Milisecond access times and 5
Megabit transfer rate. These speeds are too fast for improved
throughput with a 386 system.

This may not hold true for 25MHZ or 50Mhz 486 systems with an EISA or
microchannel bus.

Steve Ludlum  Industrial Bytes & Bits   Cambridge, MA  ima!sludlum!stevel
Steve Ludlum  Industrial Bytes & Bits   Cambridge, MA ima!sludlum!stevel

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