Tappan@bbng.arpa (Dan Tappan) (02/26/86)
I'm looking for some practical information on SCSI hard disk controllers. Basicly I'm looking for a controller I can use to connect an ST506 drive to a Macintosh, using either the Mac+ SCSI port or one of the MacSCSI varients (I haven't decided which way I'm going to go in upgrading my Mac). Looking through the adds in the back of BYTE I find the following controllers mentioned: Xebec S1410A - I assume this is the most likely to be standard. It's also the most expensive. OMTI 20L Shugart 1610-1 "Similar to DTC 510" Shugart 1610-3 "Similar to Xebec S1410" Shugart 1610-4 "Similar to Adaptec 4000" Also mentioned are Western Digital, Adaptec, and "DG" controllers. I don't know the model numbers. Is there anyone out there who is familiar with the SCSI spec and any of these controllers and can tell me how likely they are to work? I'm particularly interested in electrical compatability since I assume that I can hack up a driver if necessary if the controller only varies in command codes. Things like "that controller assumes it's the only one on the bus" would also be interesting. Thanks for any info, Dan Tappan -------
bmw@aesat.UUCP (Bruce Walker) (03/04/86)
[This message was transmitted with %100 recycled characters.] In article <1300@brl-smoke.ARPA> Tappan@bbng.arpa (Dan Tappan) writes: [...] >Basicly I'm looking for a controller I can use to connect an ST506 >drive to a Macintosh, using either the Mac+ SCSI port or one of the >MacSCSI varients [...] > Looking through the adds in the back of BYTE I find the > > Xebec S1410A - I assume this is the most likely to be standard. > It's also the most expensive. ^^^^--------------[I assume you mean LEAST expensive] > OMTI 20L > Shugart 1610-1 "Similar to DTC 510" > Shugart 1610-3 "Similar to Xebec S1410" > Shugart 1610-4 "Similar to Adaptec 4000" > Also mentioned are Western Digital, Adaptec, and "DG" controllers. I > don't know the model numbers. > [...] >I'm particularly interested in electrical compatability [...] First off, the Xebec and OMTI are SASI controllers, but in essence, SASI is a subset of SCSI, so there would be no problem connecting them to a SCSI port (that is, *assuming* that Apple doesn't screw up and produce a non-standard SCSI implimentation). The Xebec comes wired to expect a single host (your computer), single controller (itself) and no arbitration (nobody else on the bus) situation; but this can be changed by jumpering. Basically, SCSI is SCSI. You should be able to get any host adapter that says SCSI on it and hook it up, and, if you are only doing simple things like reading/writing a number of sectors, have it running with your software in no time. If you are connecting a single ST506 to a single Mac, your best bet is to shop for the least expensive board you can get from the list above. You do not need any more functionality (unless you are very concerned about controller-handled sector defect mapping or something, in which case, you'll have to get the individual OEM manuals and investigate). If, on the other hand, you wanted an "all singing, all dancing" bells and whistles board (possibly with 2,7 RLL encoding to boost your disk capacity and transfer rate by 50%), then spring for an Adaptec. One small point: all the above boards have a 50 pin Berg-style flat ribbon connector for the SCSI (or SASI) port. Some PC host adapters I have seen (and potentially the Apple too) use a 25 or 36 pin D-shell which, of course, will require some kind of transition cable. These can be an absolute bitch to make, check out the price of cables while you're out shopping. Bruce Walker {allegra,ihnp4,linus,decvax}!utzoo!aesat!bmw Join the march to save individuality! +--------------------------------------------------------+ | This disclaimer is not warranted to be suitable or fit | | for any purpose whatsoever, and may be recursive. | +--------------------------------------------------------+