neese@adaptex.UUCP (03/15/90)
>>Also, I'd go with the SCSI instead of the ESDI interface. It gives you more >>options and connectivity. True. >Before you commit to SCSI, make sure that the applications you will want >to run will support SCSI. For instance, Microsoft will not guarantee >that Windows will work with SCSI. This is true to a degree. For instance, Windows386 made no provisions for bus master host adapters like the AHA-154x or WD7000 adapters. Adaptec provides a freebie driver to work around this problem and Windows386 runs fine with this driver. But I consider this a band-aid. The companies that supply virtual 386 programs have been working very hard together to develope and implement a specification called VDS (Virtual Device Support) that will alleviate this problem entirely. It makes provisions for bus masters and allows them to run without any drivers. Adaptec and I am sure WD also, is aggressively pursuing this. It does take some work on the part of the host adapter vendor to implement this, but it is happening. >Also, not all SCSIs are alike. Make sure that the peripherals you want >will work with the SCSI host adaptor you choose. This for the most part correct. But SCSI devices available today are much better than those available a year ago. There are still those that do not correctly implement the standard. The AHA-154xA adapter is very picky about a device that does not adhere to the standard. This is due to the SCSI bus being completely in hardware. There are adapters that implement the bus in software. Those adapters can be made to work around the oddities in a vendor's implmentation. This is rather unfortunate. The only way to force the vendor's to get the problem corrected is for all the adapter companies to scream thier heads off. We do this on a regular basis. It has made a difference. Also add that vendor's are becoming more aware that SCSI is gaining popularity, so they will do anything they can to get thier device up to the standard. It is easy to tell which companies are serious about SCSI. Look at the line of devices they carry first. If the line is mostly ESDI and some SCSI, then you can bet that SCSI is a sideline business. Companies like Quantum, make thier living on SCSI. They do it better than anyone in the industry. CDC (Imprimis/Seagate) are good at it also. They have consistently introduced SCSI based drives first and ESDI second in the last 2 years. >I suggest you avoid SCSI until the SCSI manufacturers come to some >agreement about standards. Unless you are much luckier than I, the >standard they settle on will differ from the one you buy. I would not suggest anyone avoids SCSI. I would rather say, that you should be intelligent about choosing SCSI. SCSI is not for everyone. Selecting the peripherals can be a chore. I have been running SCSI peripherals for the last 3 years and have never had any troubles (from vendors such as CDC, Quantum, Maxtor, Cipher, Archive, Sony, Toshiba, Hitachi, WangDAT, Exabyte, and Fujitsu). On the other hand I do know of people who have had nothing but troubles. These are usually related to a CPU that can't support the adapter or a 5 year old SCSI drive, which may be more SASI than SCSI. People that have the most problems are those who have put together thier own CPU from scratch with some mother board built by someone else. But even these are getting better. Roy Neese Adaptec Central Field Applications Engineer UUCP @ {texbell,attctc}!cpe!adaptex!neese merch!adaptex!neese uunet!swbatl!texbell!merch!adaptex!neese