oakley@cgfsv1.dec.com (SPS Guy) (04/24/87)
I have been lucky to pick up a pair of Seagate ST-412 10 Mb drives, which are I beleive of the SCSI persuasion. Being highly desirous of a hard drive on my A1000 I was wondering if anybody had picked up one of the SCSI Interfaces available (eg: CLtd) and been able to plug one of the (ex)IBM type drives into it. I know the result will look messy but the drives were the right price and larger drives are more plentiful in that other market. I'm not afraid to experiment but would like some hope for success prior to starting. waymor
grr@cbmvax.cbm.UUCP (George Robbins) (04/25/87)
In article <9475@decwrl.DEC.COM> oakley@cgfsv1.dec.com (SPS Guy) writes: > > I have been lucky to pick up a pair of Seagate ST-412 10 Mb drives, >which are I beleive of the SCSI persuasion. OOPS - if they are ST-412, then they are not SCSI. SCSI drives are best identified by having a 50 pin header connector for the signal cable. They are not often (if ever) seen in sizes as small as 10 MB. Your drives are ST-506 compatible. Actually the ST-412 is also a semi-standard, the difference being a "buffered seek" capability. You should be able to find a controller that can use these drives. Keyword being ST-506. Some adapter boards are available to provide as SCSI interface for ST-506 drives, but you will need to spend $$$ otherwise unneeded. -- George Robbins - now working for, uucp: {ihnp4|seismo|rutgers}!cbmvax!grr but no way officially representing arpa: cbmvax!grr@seismo.css.GOV Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)
jimmyb@well.UUCP (04/27/87)
ST-412/506 type drives MUST use an SCSI controller to communicate with your scsi HOST ADAPTER. I am currently putting such a beast together useing a 20mb 3.5 inch hard drive. The controller I am using is an ADAPTEC ACB4000a. This controller will allow you to run 2 drives from it. So you would effectivly have a 20 meg system. If I may I recommend you talk to Jeff at sunnyvale memories at 1-800-262-disk. or inside california 1-800-922-disk. He sells the 4000a for aprox 165 bucks. The ACB4000a is a fully SCSI hard disk controller with a 50 pin interfaceing cable. Of course after you put the drive system together you have to have something to talk to it. The least expensive host adapter out at the time is the Cltd. SCSI interface. I belive it was designed with the adaptec series in mind. (I only leafed thru the manual at the local store so Im not sure about that last one.) Any brave soul KNOW what type of Controller the Cltd drive uses?? Disclaimer: I never use disclaimers.
blgardne@esunix.UUCP (04/29/87)
in article <1730@cbmvax.cbmvax.cbm.UUCP>, grr@cbmvax.UUCP says: > In article <9475@decwrl.DEC.COM> oakley@cgfsv1.dec.com (SPS Guy) writes: >> I have been lucky to pick up a pair of Seagate ST-412 10 Mb drives, >>which are I beleive of the SCSI persuasion. > > OOPS - if they are ST-412, then they are not SCSI. SCSI drives are best > identified by having a 50 pin header connector for the signal cable. They > are not often (if ever) seen in sizes as small as 10 MB. So how about a brief tutorial on how to recognize SCSI vs ST506? If I'm looking a "raw" hard drive and it has a 50 pin edge card connector it's SCSI, is that what you're saying George? Or are you referring to a 50 pin DB type connector on an enclosed drive? What kind of connections does a ST506 drive have? And where does SASI fit in here? Does ST506 = SASI = IBM PC hard drive? I realize that SCSI has lots of potential for huge storage expansion, but a lot of Amiga SCSI stuff I've seen seems to be going around in circles. What I mean is Amiga -> SCSI then SCSI -> ST506 drive. Why waste the hardware (and money!) on SCSI if the drive being used is simply the more limited ST506? Or am I barking up the wrong tree? -- Blaine Gardner @ Evans & Sutherland UUCP Address: {ihnp4,decvax}!decwrl!esunix!blgardne Alternate: {ihnp4,seismo}!utah-cs!utah-gr!uplherc!esunix!blgardne
farren@hoptoad.uucp (Mike Farren) (05/02/87)
In article <78@esunix.UUCP> blgardne@esunix.UUCP (Blaine Gardner) writes: > So how about a brief tutorial on how to recognize SCSI vs ST506? If >I'm looking a "raw" hard drive and it has a 50 pin edge card connector >it's SCSI, is that what you're saying George? Or are you referring to a >50 pin DB type connector on an enclosed drive? An ST-506 drive has two card edge connectors - one 34 pin (17 on a side) and one 20 pin (10 on a side). SCSI drives have one 50 pin - 25 on a side. > What kind of connections does a ST506 drive have? And where does SASI >fit in here? Does ST506 = SASI = IBM PC hard drive? > > I realize that SCSI has lots of potential for huge storage expansion, >but a lot of Amiga SCSI stuff I've seen seems to be going around in >circles. What I mean is Amiga -> SCSI then SCSI -> ST506 drive. Why >waste the hardware (and money!) on SCSI if the drive being used is >simply the more limited ST506? Or am I barking up the wrong tree? First, SCSI more or less equals SASI. The interface was developed by Shugart as the Shugart Associates System Interface, and evolved into the Small Computer System Interface when it was accepted and used by other companies than Shugart. The interface is much more general than the ST-506 interface. It can accomodate other types of storage devices than just disk drives, and can allow several devices per interface without requiring each device to have its own control cable. Thus, you can put an ST-506 disk drive onto a controller which then connects to the system via an SCSI interface, and get the cheap price (and lower performance) of the ST-506 device while retaining one easy interface. Not a waste of hardware and money - you can always upgrade later, and the IBM PC marketplace will take the ST-506 off your hands... -- ---------------- "... if the church put in half the time on covetousness Mike Farren that it does on lust, this would be a better world ..." hoptoad!farren Garrison Keillor, "Lake Wobegbvi 2 2
spencer@eris.BERKELEY.EDU (Randy Spencer) (05/03/87)
In article <2084@hoptoad.uucp> farren@hoptoad.UUCP (Mike Farren) writes: >In article <78@esunix.UUCP> blgardne@esunix.UUCP (Blaine Gardner) writes: >> So how about a brief tutorial on how to recognize SCSI vs ST506? > >An ST-506 drive has two card edge connectors - one 34 pin (17 on a >side) and one 20 pin (10 on a side). SCSI drives have one 50 pin - 25 >on a side. ...but it's not an edge connector... The REAL SCSI connector looks like this: [][][][][][][][][][][][][][][][][][][][][][][][][] [][][][][][][][][][][][][][][][][][][][][][][][][] it plugs into pins sticking out from a PC board, or there are chassis mounts that have the same connector. Infact, this is exactly the kind of connector that the Supra hard disk uses. But, just because there is a standard, doesn't mean that people have to use it :'), actually to plug in SCSI drives this connector would require a ribbon cable, so some hard disk manufactures have gone to various types of connectors. The plugs on the back of the old C-LTD. hard disk boxes (like, umm... let's see, Fred has one, Bob has one, Marnix has one, and Tom just got one, and these connectors are not connected to anything) are standard in the Mac hard disk world for SCSI (you see, the C-LTD. box has a ribbon cable sneak in the crack in the box, and by-pass the connectors all together, the box is actually made by Rodime for the Mac, or was, C-LTD. is finally making their own boxes with Adaptec controllers to ST506 type drives). This non-connected connector is like (possibly exactly like) a Centronics connector, like your Epson printer has on it (don't plug your parallel port into it though!) The other kind is used in Mike's Xebec. It is also on the Microbotics hard disk (this is the one that you _do_ plug into the parallel port). This connector is a DB-50. Take a look at the serial connector on the back of your Amiga and imagine it being twice as wide. But if you open any of the drives mentioned above (I have) you will find the good old standard SCSI connector inside that is pictured above. >First, SCSI more or less equals SASI. Let me define some terms first: HOST ADAPTER, this is the board that plugs into the side of your Amiga and has a SCSI plug on the back of it, eventually it may also mean a card inside a Zorro cage, but there arn't any yet. SCSI INTERFACE, this is the card that takes the SCSI signal coming over the cord from the Host Adapter, and translates it into commands for an ST506 type Hard Disk. Well, as I understand it, the Host Adapters that are coming out for the Mac and the Amiga more or less equals SASI, but that is not the way that SCSI is defined. The full SCSI spec supports buss arbitration and disconnect/reconnect. This allows you to hook up more than one host to more than one drive. This is actually what I am interested in doing. I have two Amigas in the same house (and soon to get a Mac) and I want to have hard disks on both Amigas. If there was support for buss arbitration than I could hook up two Amigas to one SCSI drive and not have to have two hard disks with the same files on them. Actually, I think that I can hook two Amigas to one drive if I can change the ID number that the Amiga responds to, but if there is no buss arbitration and both drives ever try to access the disks at the same time...BOOM! Not being able to hook both machines to the same SCSI buss wouldn't be a big deal if I was just putting up a 20 meg drive, but I expect to have hundreds of megs of stuff (I have hundreds of disks already to go). To pay for twice the amount of drives does not make sense for two machines that are placed ten feet apart. (I could even carve out a chunck for the Mac to use, but the built in SCSI on the Mac don't support buss arbitration either.) The other thing that is useful is what is called disconnect/reconnect. If I have those two machines hooked up through the mysterious SCSI host adapter that supports buss arbitration I can still have contention (we all know that word). If I have a BBS running on one Amiga (I do) and I am compiling on the other, and a call comes in, the BBS wants to talk to the hard disk, but my compile is using the SCSI buss, so the BBS will time out, and the user will get hung up on. With disconnect/reconnect when the host adapter issues a command to the SCSI interface on the hard disk, the interface will disconnect and free up the SCSI buss until the command is done. That is when the BBS could get in a command to the SCSI interface's command buffer. When the interface has the info ready for the first host it reconnects to it as soon as it can (that host may be issuing a command to another hard disk). I know that this hasn't made the choice much easier, and probably clouded the SCSI issue, but I would like to see these points addressed by the HD makers. Or you could just get me an extra serial port and I will run SLIP/TCP between the two Amigas. Nothing like compiling over the serial port. "Boy Randy, you really sound like a candidate for an expansion chassis" No, If I had gotten one last month, I would have been kicking myself this month when I saw that I could have gotten an even uglier one now. So if I get the new CSA tower (it really is ugly) someone would come out with an even uglier one, and again I would be kicking myself. One last thing to mention about the different hard disks (you thought I was done) is that every different one uses incompatible setups. If I take C-LTD. formatted SCSI hard disk and plug it into the Xebec, it would not be able to recognize it. The Xebec uses a parameter file on the boot disk, and the hard disk. The C-LTD. uses a mountlist entry. I don't remember the Microbotics set up, but I couldn't get that drive to daisy chain to anybody elses hard disk. So the idea of unplugging at one house and going to another still only exists on the Macintosh. Any ideas how this incompatibility will be handled on the ASDG, and the C/A, and the Byte by Byte SCSI? What will happen to all our Host Controller cards when 1.3 comes out and wants to boot off the hard disk? Seems that there should be a standard way to make a controller card. I guess that we are watching the same thing that the Mac went through about a year and a half ago before their SCSI standard (sub standard). >Mike Farren that it does on lust, this would be a better world ..." -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Randy Spencer P.O. Box 4542 Berkeley CA 94704 (415)284-4740 I N F I N I T Y BBS: (415)283-5469 Now working for |||||||||||::::... . . BUD-LINX But in no way |||||||||||||||::::.. .. . Officially representing ||||||||||||:::::... .. ....ucbvax!mica!spencer s o f t w a r e spencer@mica.berkeley.edu -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-