sanand@sp90.uucp (01/05/91)
> Can anyone tell me what the difference is between Adaptec's 1542A and > 1542B SCSI controllers is? I am planning on using one of them in an ACMA > 386/20 system with a Maxtor SCSI drive. I have heard of problems with the bus > Kevin W. Rudd > Sequent Computer Systems > I am not sure of all the differences, but the major one is that "B" has a floppydisk controller, "A" doesn't. I run the "B" with a Maxtor, so far (touch wood) no problems. Sanand.
larry@nstar.rn.com (Larry Snyder) (01/06/91)
sanand@sp90.uucp writes: >> Can anyone tell me what the difference is between Adaptec's 1542A and >> 1542B SCSI controllers is? I am planning on using one of them in an ACMA >> 386/20 system with a Maxtor SCSI drive. I have heard of problems with the bus >> Kevin W. Rudd >> Sequent Computer Systems >> >I am not sure of all the differences, but the major one is that "B" has >a floppydisk controller, "A" doesn't. I run the "B" with a Maxtor, so far >(touch wood) no problems. Wrong - both the 1542A and the 1542B has a floppy controller - the 1540 family doesn't have the floppy controller build on the board. -- Larry Snyder, NSTAR Public Access Unix 219-289-0282 (HST/PEP/V.32/v.42bis) regional UUCP mapping coordinator {larry@nstar.rn.com, ..!uunet!nstar!larry, larry%nstar@iuvax.cs.indiana.edu}
fmiller@dobie.UUCP (Fred Miller) (01/07/91)
In article <1991Jan5.045321.1799@sp90.uucp>, sanand@sp90.uucp writes: > > Can anyone tell me what the difference is between Adaptec's 1542A and > > 1542B SCSI controllers is? I am planning on using one of them in an ACMA > > 386/20 system with a Maxtor SCSI drive. I have heard of problems with the > > bus. The "A" & "B" designations are revisions...the latest being the "B" revision, and soon a "C" version. I don't know the specifics in the differences. I have the 1542B installed and have had NO problems! Fred
sralston@srwic.UUCP (Steve Ralston) (01/08/91)
In article <1991Jan5.045321.1799@sp90.uucp> sanand@sp90.uucp writes: >> Can anyone tell me what the difference is between Adaptec's 1542A and 1542B >> SCSI controllers is? >> Kevin W. Rudd >> Sequent Computer Systems > > I am not sure of all the differences, but the major one is that "B" has > a floppydisk controller, "A" doesn't. I run the "B" with a Maxtor, so far > (touch wood) no problems. > Sanand. BzzzT, Wrong! The Adaptec 1542B is a later rev of the 1542A; they both have a floppy controller interface. The 1542B is a smaller, 2/3 length board (probably has more surface mount chips) than the 1542A full length board. The 1540B (and 1540A) are SCSI *only* boards (no floppy controller) that you're probably thinking of. I believe the 154xA and 154xB are, otherwise, functionally equivalent. Hopefully, if Roy Neese (neese@adaptex) is watching he will respond with the technical low-down on any differences. -- Steve Ralston sralston@srwic.UUCP 235 N Zelta voice: 316-686-2019 Wichita, KS 67206 ..!uunet!ncrlnk!ncrwic!srwic!sralston
keith@sequoia.execu.com (Keith Pyle) (01/08/91)
In article <1991Jan5.045321.1799@sp90.uucp> sanand@sp90.uucp writes: >> Can anyone tell me what the difference is between Adaptec's 1542A and >> 1542B SCSI controllers is? I am planning on using one of them in an ACMA >> 386/20 system with a Maxtor SCSI drive. I have heard of problems with the bus >> Kevin W. Rudd >> Sequent Computer Systems >> > >I am not sure of all the differences, but the major one is that "B" has >a floppydisk controller, "A" doesn't. I run the "B" with a Maxtor, so far >(touch wood) no problems. > >Sanand. This isn't quite correct. The 1542B is a newer model of the 1542A and is a two-thirds length card instead of the full-length used for the 1542A. Both the 1542A and 1542B are intelligent controllers which support floppy as well as SCSI drives. The floppy portion can be disabled by a jumper, if desired. If I remember correctly, the 1540 series is the SCSI only controller (i.e., no floppy). Whether there are A and B versions of it, I'm not certain, but I think there are. The 1542A and B are supposed to be functionally identical, I believe. However, I have one machine running a 1542A in a 286 that works fine with Fastback 2.01. Just toying around with a 1542B in the same configuration, I found that the system would hang during the DMA tests that Fastback runs (specifically, the medium speed DMA check). I haven't had the time yet to really run this down. -- ----------------------------------------------------------------------------- Keith Pyle UUCP: ...!cs.utexas.edu!execu!keith Execucom Systems Corp., Austin, Texas Internet: keith@execu.com "It's 10 o'clock. Do you know where Disclaimer: Everything I say is your child processes are?" true unless I use the word 'the'. -----------------------------------------------------------------------------
scjones@thor.UUCP (Larry Jones) (01/09/91)
The 1542B uses high-density custom ICs to reduce the number of parts on the board (and I believe the board is smaller as well) as compared to the 1542A. They are functionally identical. ---- Larry Jones UUCP: uunet!sdrc!thor!scjones SDRC scjones@thor.UUCP 2000 Eastman Dr. BIX: ltl Milford, OH 45150-2789 AT&T: (513) 576-2070 I keep forgetting that rules are only for little nice people. -- Calvin