[net.micro.pc] PC-DOS Multiple Hard Disks

alexande@drivax.UUCP (04/28/86)

In article <660@nicmad.UUCP> brown@nicmad.UUCP (Mr. Video) writes:
>Most hard disk controller boards will allow you to connect up 2 hard drives.
>Both of which, must be the same size.  You tell the controller, via jumpers,
>what size drive is attached.

The controllers I have examined or used (Xebec, WD, Adaptec) have separate
jumpers for each drive, so you CAN use different size drives.  This feature
is supported by the ROM BIOS on the controller card.

>The 34 or 40 pin (I forget which) has two connectors
>on it.  It then connects up like the floppies are.  The other smaller cable
>is separate, so there is one per drive.

Actually, there is a 34 pin cable (the data cable) that connects to both
drives, and a 20-pin cable (the control cable) for each drive.

Also, don't forget to remove the termination resistor pack on all drives
except the last one on the 34-pin cable chain.  Things usually work without
this precautionary measure, but the drive and controller makers want you
to do it anyway.
--
#include "disclaimer.h"
#include "quote.h"
-- Mark Alexander   {ihnp4,mot,ucscc,ucbvax!hplabs!amdahl} !drivax!alexande
-- 
--
#include "disclaimer.h"
#include "quote.h"
-- Mark Alexander   {ihnp4,mot,ucscc,ucbvax!hplabs!amdahl} !drivax!alexande

brown@nicmad.UUCP (04/29/86)

In article <464@drivax.UUCP> alexande@drivax.UUCP (Mark G. Alexander) writes:
>In article <660@nicmad.UUCP> brown@nicmad.UUCP (Mr. Video) writes:
>>Most hard disk controller boards will allow you to connect up 2 hard drives.
>>Both of which, must be the same size.  You tell the controller, via jumpers,
>>what size drive is attached.
>
>The controllers I have examined or used (Xebec, WD, Adaptec) have separate
>jumpers for each drive, so you CAN use different size drives.  This feature
>is supported by the ROM BIOS on the controller card.

Unfortunately, the controller that Kamerman Labs is now using (OMPTI), only
has one set of jumpers for size.  So, thanks for the info.  I will have to keep
that in mind when I order more hard disk systems.  I will point that out 
to them and hear what they have to say about it.

>>The 34 or 40 pin (I forget which) has two connectors
>>on it.  It then connects up like the floppies are.  The other smaller cable
>>is separate, so there is one per drive.
>
>Actually, there is a 34 pin cable (the data cable) that connects to both
>drives, and a 20-pin cable (the control cable) for each drive.

I was at home when I wrote this, so I couldn't remember the numbers, but
at least I said smaller cables.  Sorry about the mis-information.
-- 

              ihnp4------\
            harvard-\     \
Mr. Video      seismo!uwvax!nicmad!brown
              topaz-/     /
             decvax------/