> Hi there,
> I saw an interesting offer for an EISA system which includes a 330 MB SCSI disk
> and the Bustek EISA-SCSI controller (742). Now, that there is a Adaptec-1742
> I would really like to get this one. However, this would add to the cost
> of the system. Now, my question is whether these controllers are compatible.
According to BusTek, their BT-742A supports a "superset of AHA-154xB register
and command protocol". I've heard, but not verified, that their emulation
is very good.
Quote:> I know that the Bustek and the Adaptec-1740 will work with OS/2 2.0. What I
> don't know is will these work with Dell or Interactive UNIX and 386BSD-UNIX
> and especially the Adaptec-1742 with OS/2 2.0.
Interactive UNIX has BusTek drivers packaged with it (and if nothing
else, you can use the 1542B compatibility).
According to documents I've collected, here is a comparison of the two cards:
Adaptec AHA1742 BusTek BT-742A
Bus EISA EISA
Interface SCSI-2 SCSI-2
"Fast" SCSI-2 xfers Yes No
Bus width 32 bits 32 bits
Hard + Floppy support 2+5H + 2F 2+5H + 2F (Note 1)
Maximum xfer rate <2Ma, <10Ms <5Ma, <5Ms (Note 2)
Burst xfer rate 33MB/Sec 33MB/Sec
Dos address limit 1 GB 1 GB (Note 3)
Read-ahead buffer size N/A 128 Bytes
Emulation N/A AHA154xB
On-board processor type ??? 80188
External Connector SCSI-2 Centronix 50-way
Note 1: Two hard drives are supported directly in DOS via the on card BIOS,
the other drives must use separate driver software (ASPI)
Note 2: "Ma" means MB/Sec asynchronous
"Ms" means MB/Sec synchronous
Note 3: This is reported as the "maximum capacity that can be recognized
under DOS". I don't know whether that means in a single partition,
or for the disk as a whole.
As with many things in life, this is something you will have to decide for
Quote:> In other words, is it worth
> the trouble and cost of changing the Bustek-742 to an Adaptec-1742 ?
yourself. If you're planning on using synchronous transfers, then the
AHA1742B claims twice the speed of the BusTek. It's reversed for
asynchronous transfers. ( A quick scan through my various disk drive
specs indicate Asynchronous transfer rates are typically between 1.5 and
4 MB/Sec; Synchronous transfer rates seem to be between 4 and 10 MB/Sec.
[An interesting aside, is that some of the drives with the fastest
synchronous rates, have the slower asynchronous rates.] )
> Norbert Bladt, Ascom Autelca AG, Worbstr. 201, CH-3073 Guemligen, Switzerland Hope this helps,
> Phone: +41 31 999 65 52 FAX: +41 31 999 65 44
Richard D. Nichols
Teradyne Inc., Telecommunications Division
Phone: (708) 940-9000