kling@ICS.UCI.EDU (Rob Kling) (11/11/90)
Hi ... I have an AST premium 386/90c with an 80MB ESDI drive. I am running out of real estate & am contemplating getting a 2nd (HH) hard drive (as well as a 3.5" floppy, thus the preference for half-height). For cost reasons, I was interested in adding a Connor IDE drive w/a controller card. A local shop claims that I can't mix drive types, even if I add drive controller cards. The people I deal with at this shop read catalogs, locate sources of supply, negotiate prices, and have a tech "in the back" who can install simple things. I find their claims about controller incompatibilities puzzling .... But it may be based on some installation problems their tech had. I'm curious if anyone "out in netland" has found that simple mindedly adding a controller of a different type to an existing system makes it straightforward to include different types of drives in the same system. (Is this simple, are there nuances in installation/configuration?) Why can't MFM & ESDI or ESDI & IDE be co-resident in the same system as long as the controllers are appropriate? Any comments/explanations about why there might be incompatibilities if the appropriate drives are each connected to a proper controller for that kind of drive? Thanks in advance Rob Kling Information & Computer Sci UC-Irvine
feustel@netcom.UUCP (David Feustel) (11/11/90)
IDE drive controllers usually respond to the IO address reserved for the standard AT mfm (read WD1003) controller; hence an IDE controller cannot coexist with the mfm controller unless one of the controllers has been set to respond to the alternate hard disk io address. Unfortunately, dos doesn't know about the alternate io address, so whichever controller is setup for it can't be used in dos. ESDI and SCSI controllers typically respond to a different set of io address than the AT mfm addresses; therefore they can coexist with the mfm OR IDE controller. -- David Feustel, 1930 Curdes Ave, Fort Wayne, IN 46805, (219) 482-9631
jca@pnet01.cts.com (John C. Archambeau) (11/11/90)
kling@ICS.UCI.EDU (Rob Kling) writes: >Any comments/explanations about why there might be incompatibilities >if the appropriate drives are each connected to a proper controller for >that kind of drive? Simple, because ESDI, IDE, and ST412/506 use the same port addresses. An IDE drive looks to your system like an ST412/506 drive to your system BIOS. What you could probably do is set your ST412/506 MFM controller card to the secondary port address, but then you have a problem of setting it to the second interrupt. Not to mention that MS-DOS doesn't care to play with second controllers. Only big exception is SCSI. Your SCSI host adaptors are designed to work with an existing ST412/506, ESDI, or IDE drive already in your system. // JCA /* **--------------------------------------------------------------------------* ** Flames : /dev/null | Small memory model only for ** ARPANET : crash!pnet01!jca@nosc.mil | Unix? Get the (*bleep*) out ** INTERNET: jca@pnet01.cts.com | of here! ** UUCP : {nosc ucsd hplabs!hd-sdd}!crash!pnet01!jca **--------------------------------------------------------------------------* */
stevek@hpfcmgw.HP.COM (Steve Kauder) (11/12/90)
I am NOT a technical expert, but I do believe you can add a "hard card" drive to your systems. You know, this is one of those with a "low profile" disk attached directly to an 8 or 16 bit card. I believe such things come with their own drivers and can be used in addition to an mfm or ide or ... controller. The big advantage -- you get to keep what you've already got. I have an st-506 controller for a 40mb drive. I have been planning to get one of these hard cards to add to my system. I think the best deal yet is probably the brand-new Hard Card XL with 105 mb (expected to sell for $700). Please check out any above facts or guesses before investing your money -- you'll be happier. sk
kls30@duts.ccc.amdahl.com (Kent L Shephard) (11/16/90)
In article <5569@crash.cts.com> jca@pnet01.cts.com (John C. Archambeau) writes: >kling@ICS.UCI.EDU (Rob Kling) writes: >>Any comments/explanations about why there might be incompatibilities >>if the appropriate drives are each connected to a proper controller for >>that kind of drive? > >Simple, because ESDI, IDE, and ST412/506 use the same port addresses. An IDE >drive looks to your system like an ST412/506 drive to your system BIOS. > >What you could probably do is set your ST412/506 MFM controller card to the >secondary port address, but then you have a problem of setting it to the >second interrupt. Not to mention that MS-DOS doesn't care to play with second >controllers. Wrong! Buy a controller designed to act as a secondary controller in the system. It WILL work if the controller has its own bios. Since the device has its own bios MS-DOS WILL play with a secondary controller. MS-DOS will play with ANYTHING provided you have a bios level driver or an installable device driver. I know because I have a DTC controller that works as the second controller in my system and I've also designed a couple of interface boards for PC's that were definitely non-standard and MS-DOS played just fine. > >Only big exception is SCSI. Your SCSI host adaptors are designed to work with >an existing ST412/506, ESDI, or IDE drive already in your system. SCSI is a good option because, if you ever change computer systems (Mac NeXT, Amiga, SUN) you can reuse the SCSI drive. > > // JCA > > /* > **--------------------------------------------------------------------------* > ** Flames : /dev/null | Small memory model only for > ** ARPANET : crash!pnet01!jca@nosc.mil | Unix? Get the (*bleep*) out > ** INTERNET: jca@pnet01.cts.com | of here! > ** UUCP : {nosc ucsd hplabs!hd-sdd}!crash!pnet01!jca > **--------------------------------------------------------------------------* > */ -- /* -The opinions expressed are my own, not my employers. */ /* For I can only express my own opinions. */ /* */ /* Kent L. Shephard : email - kls30@DUTS.ccc.amdahl.com */
jca@pnet01.cts.com (John C. Archambeau) (11/16/90)
kls30@duts.ccc.amdahl.com (Kent L Shephard) writes: >In article <5569@crash.cts.com> jca@pnet01.cts.com (John C. Archambeau) writes: >>kling@ICS.UCI.EDU (Rob Kling) writes: >>>Any comments/explanations about why there might be incompatibilities >>>if the appropriate drives are each connected to a proper controller for >>>that kind of drive? >> >>Simple, because ESDI, IDE, and ST412/506 use the same port addresses. An IDE >>drive looks to your system like an ST412/506 drive to your system BIOS. >> >>What you could probably do is set your ST412/506 MFM controller card to the >>secondary port address, but then you have a problem of setting it to the >>second interrupt. Not to mention that MS-DOS doesn't care to play with second >>controllers. > >Wrong! Buy a controller designed to act as a secondary controller in the >system. It WILL work if the controller has its own bios. Since the >device has its own bios MS-DOS WILL play with a secondary controller. But try and find such controllers. My WA3-16 (WD1003-WA2 clone, same chip set) has the ability to be configured as a secondary controller, BUT it has no on-board BIOS which means you need an OS that is 'aware' of a secondary ST412/506 MFM controller to use this feature of the WA3-16 (same case applies to WD1003's and WD1006's). Now there's another problem with using my controller as a secondary controller under let's say Xenix. It's not a wise idea to have two controllers using the same IRQ, so you have to punt that around. But wait, you can't punt that IRQ around, it's fixed. The port address is no problem to punt around, but what about that IRQ? Well, you solder a jumper wire from the controller to the desired IRQ line. Very few hard drive controllers have the ability to punt around the IRQ. Something very desirable if you're going to have multiple controllers in your machine. >MS-DOS will play with ANYTHING provided you have a bios level driver or >an installable device driver. Never say anything. There are ALWAYS (and that's the only given in the computer industry) an exception. One big exception I've noted is the XT floppy controller with on-board BIOS for high density drives. They don't seem to work to hot. At least with my experience with them. Anything you say? Well, gee, I must be having a bad time of it all. >I know because I have a DTC controller that works as the second controller >in my system and I've also designed a couple of interface boards for PC's >that were definitely non-standard and MS-DOS played just fine. DTC you say? Well, it may work just fine under MS-DOS, but Novell Netware doesn't like it (at least ELS Level II doesn't). When a controller won't even COMPSURF, then I begin to wonder. Swapped the controller for a WD1006 and it ran with the same drive like a champ. >>Only big exception is SCSI. Your SCSI host adaptors are designed to work with >>an existing ST412/506, ESDI, or IDE drive already in your system. > >SCSI is a good option because, if you ever change computer systems (Mac >NeXT, Amiga, SUN) you can reuse the SCSI drive. Maybe I should correct you. Mac's use their own brain damaged implementation of SCSI. Drive makers such as Imprimis and Micropolis make a special version of their SCSI drives just for Macs. Note the letters in a Seagate model number with NM in them (SCSI Mac). Now there are some smart drives that you can pull off of one machine and put on another, but there are no guarrantees that it will work considering the brain damaged non-ANSI SCSI spec the Macs use. // JCA /* **--------------------------------------------------------------------------* ** Flames : /dev/null | Small memory model only for ** ARPANET : crash!pnet01!jca@nosc.mil | Unix? Get the (*bleep*) out ** INTERNET: jca@pnet01.cts.com | of here! ** UUCP : {nosc ucsd hplabs!hd-sdd}!crash!pnet01!jca **--------------------------------------------------------------------------* */