On Thu, 27 Jun 2002, Rick Moen wrote: > Quoting Andre M. V. ([EMAIL PROTECTED]): > > > Few years ago yes. But now, With Ultra ATA 100 around, > > IDE drives can compete with low/medium sscsi drives. > > They're not really directly comparable. Too different.
The original question was this: "anyway for better performance and your money's worth, go with scsi." So wer are talking about performance and cost in relation to scsi vs. eide. Consider: Standard Clock speed Bus Data Rate(command Rate) =============================================================== SCSI (SCSI-1) 5MHz 8bits 5 MB/s Fast SCSI (SCSI-2) 10Mhz 8bits 10 MB/s Wide SCSI (SCSI-2) 5Mhz 16bits 10 MB/s Now compare it with: "Huge And Fast: Western Digital WD1200JB With 8 MB Cache" http://www4.tomshardware.com/storage/02q1/020305/index.html Read Data transfer: 24-49 MB/s Read Burst Data transfer: 24-49 MB/s Write Data transfer: 14-39 MB/s Bottomline: Theoretical speed of scsi-1 and scsi-2 standard drives is no match with the actual speed of the new generation EIDE HDD. Cost effective too. > With ATA, you get bottom price per megabyte, usually higher CPU loading, 4.2% CPU usage (anandtech.com) is not a big deal. CPU usage for server and desktops are idle most of the time in the first place. > and consumption of IRQs. Answer to that is IDE raid controllers in JBOD mode. > With SCSI, you get hot-fix mapping out of bad sectors automatically, Does the HDD manufacturer already does this for you? > scatter-gather at the hardware level, ability to > do genuine low-level reformatting right in the host adapter BIOS, I certainly hope that this helps SCSI-1 and SCSI-2 HDD performance compared to the new generation EIDE drives! :) > more-stable standards, and the ability to usefully have more than one > drive per chain. See above. > And ATA 100 is a bit of a sham, because it's only barely possible to > saturate ATA 66 with fast drives under contrived test conditions, > and only one drive per chain can be active at a time. Not really a sham. In a diff. point of view you are right if you use EIDE drives the usual way.. The ATA100/133 controllers can theoretically handle 100/133 Mbytes/sec. and the current ATA HDD in the market cannot achieve those speeds. But if you use IDE RAID you can achieve speeds near 100/133 Mbytes/sec. *sustained*. regards, --- Andre M. Varon, SCSA http://andre.lasaltech.com _ Philippine Linux Users Group. Web site and archives at http://plug.linux.org.ph To leave: send "unsubscribe" in the body to [EMAIL PROTECTED] To subscribe to the Linux Newbies' List: send "subscribe" in the body to [EMAIL PROTECTED]
