TMPLee@DOCKMASTER.NCSC.MIL (08/09/90)
Recently I asked why when I installed a new DMA SCSI card I noticed no performance improvement. So far the answers I have received are that I should reformat the drive to 1:1, 2:1 or 4:1 (depending on who I talked to.) It was the tech guy at Quality Computers who said I should format it at 4:1. He didn't have a satisfactory answer to the question of why when I specified what it was being installed in, adn bought the SCSI card at the same time, that the preformatting it came with wasn't optimal. ANYWAY, this is a two part question: how can I find out what interleave it is currently formatted at, and, how do I know definitively waht it should be formatted at? (repeating, its a CMS "MacSTack" 60M drive on an Apple DMA SCSI card on a GS with an AE TWGS that has been upgraded to work with DMA.) TMPLee@dockmaster.ncsc.mil
MQUINN@UTCVM.BITNET (08/09/90)
>how can I find out what interleave it is currently formatted at, and, how >do I know difinitavely waht it should be formatted at? It should DEFINATELY be formatted at 1:1. That will give you the FASTEST read/write time. The guy at Quality Computers doesn't know what he's talking about. He probably doesn't reallize how fast the Apple HS SCSI card is, so he just figured 4:1. But I'm afraid I can't help you on finding out at what interleave yr drive is currently formatted.. If anyone else knows this, I'd really like to know too!
whitewolf@gnh-starport.cts.com (Tae Song) (08/14/90)
Although I could be wrong, I don't think 1:1 interleave is the best for Apples DMA SCSI card. It's probablely best to try out different interleaves though. MFM has 17 sectors per track, RLL has 28 (normally) and up to 34 sectors track and there's one drive with 47 sectors per track. Now, RAMFast is the only controller that can handle that much data that fast. I know Apples DMA can't do 1:1 on RLL drives. MFM drives maybe 1:1 or 2:1. I don't think the DMA SCSI cards come with low-level formatting programs, so you might have to dig out that old rev C card and low-lwvwl format starting from, I would guess 8:1 and go down to 1:1 and testing it with the DMA SCSI card. I know it's a pain, but it's the only way I can think of finding the ACTUAL optiunim interleave.
gwyn@smoke.BRL.MIL (Doug Gwyn) (08/14/90)
In article <0093B284FE618EA0.00000111@dcs.simpact.com> whitewolf@gnh-starport.cts.com (Tae Song) writes: >Although I could be wrong, I don't think 1:1 interleave is the best for Apples >DMA SCSI card. It's probablely best to try out different interleaves though. >MFM has 17 sectors per track, RLL has 28 (normally) and up to 34 sectors track >and there's one drive with 47 sectors per track. Now, RAMFast is the only >controller that can handle that much data that fast. I know Apples DMA can't >do 1:1 on RLL drives. MFM drives maybe 1:1 or 2:1. The recording modulation method is not very relevant; what is more relevant is that there is a SCSI controller between the SCSI bus and the read/write electronics. If the SCSI controller has full-track buffering, for example, then there is no point at all in trying to use other than 1:1 virtual interleave.