>From: Howie S >To: SuperMacs List >Subject: Re: [SM] Questions about a SuperMac C500 >Date: Thu, 12 Dec 2002 16:42:58 -0800 > >Hi Mark, > >I'll try and make some points that may help with your new >machine if I can. First, check this link to learn more about >your machine... http://www.lowendmac.com/supermacs/c500.shtml
Thanks for the link, Howie. >The C500 has an internal IDE bus, and only the external bus >is SCSI. My advice would be to stick with an IDE drive for your >boot drive... cheaper and just as fast or faster as SCSI >generally speaking. The external SCSI bus is 5 mb/sec, and not >considered speedy. So even if you switched that bus for internal >use, it would be half the speed of a typical internal SCSI bus. I have a few questions about this. What kind of IDE bus does the C500 have (e.g., 33.3 MB/s Mode 2 Ultra DMA, 16.6 MB/s Mode 4 PIO, 16.6 MB/s Mode 2 multi-word DMA, etc.)? What is the difference between an internal bus and an external bus? The C500 has an external DB-25 SCSI connector and an internal 50-pin SCSI connector. The CD-ROM drive is connected to the 50-pin SCSI connector with a ribbon cable. What do you mean by "switching that bus for internal use"? All I did was replace the ribbon cable (which only had one connector) with a ribbon cable that had two connectors so I could hook up both the SCSI hard drive and the CD-ROM drive. I think I disabled the terminator on the CD-ROM drive and activated the terminator on the hard drive. Hard drives can never actually match the theoretical transfer rates of the interface they're attached to. The IBM SCSI hard drive I'm using can achieve a sustained transfer rate of 3.8-5.7 MB/sec. The burst transfer rate could not exceed 10 MB/sec (the interface limit). I'm sure the drive could saturate the 5 MB/sec SCSI bus, but I wonder how badly the performance would actually suffer from it. Just for the fun of it, I'd like to run some benchmarks to compare the performance of the Western Digital UDMA/33 drive and the IBM Fast-SCSI2 drive in a C500. Even on a 5 MB/sec SCSI bus, the IBM drive has some advantages over the Western Digital (seek time, latency, cache size, etc.) and I wonder how much difference theoretical transfer rates make in the real world. Can you recommend some benchmarking software? >Your C500 may have been shipped with OS 7.6.1, but it will work >happily with any OS from 7.6 to 9.1. The trick is that when trying >to install a new OS via an Apple Install CD, the CD driver on that >install CD doesn't support the CDROM drive in the UMAX machines, >and therefore can't boot from the Apple CD. If you can boot from >an external hard drive that has a compatible CD driver on it, and >just insert the Apple CD, you can then do an OS install. In other >words, it isn't always necessary to boot from the Apple Installer >CD providing you have another device to boot from instead. You can >get a compatible CD driver (Apple CDROM 5.3.1) from here... >http://www.macdrivermuseum.com/disk.html Thanks for the link. >As for a hard disk driver, I always suggest sticking with Apple drivers. Although Apple Drive Setup doesn't recognize all drives, >and you may need to use a different utility. If so, I think it's >best to avoid older versions of FWB hard disk toolkit. Too many >trouble reports with the old versions. I've been able to boot from the original IDE hard drive, a floppy, an Apple 2x CD-ROM drive, and a 230MB SCSI hard drive. I haven't been able to boot from the IBM SCSI hard drive (which was initialized on another machine) or the Toshiba 12X CD-ROM drive or a CyberDrive 24X CD-ROM drive. I tried to use the Apple CD-ROM 5.4 driver, but it didn't help. I'm still not sure which drivers I need, or whether I need to re-initialize the IBM SCSI hard drive. >All the best, > >-Howie Thanks for your help! Mark _________________________________________________________________ Add photos to your e-mail with MSN 8. Get 2 months FREE*. http://join.msn.com/?page=features/featuredemail -- SuperMacs is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | Service & Replacement Parts [EMAIL PROTECTED] | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> SuperMacs list info: <http://lowendmac.com/supermacs/list.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/supermacs%40mail.maclaunch.com/> --------------------------------------------------------------- >The Think Different Store http://www.ThinkDifferentStore.com ---------------------------------------------------------------
