rick@Apple.COM (Rick Auricchio) (05/24/89)
Just a quick note on what to use for the mkfs parameters for "gap" and "blocks/cyl". Use 1 and 1. My tests have verified the observation that things are markedly slowed down by the bogus defaults of 7 and 400. I'm now changing those defaults to 1 and 1 for a future (post-1.1) release. Use of 1 & 1 works fine on the drives I have here; Quantums have partial and full-track buffering, hence they work well at 1-1 interleave. Seagates don't have onboard buffering, but A/UX 1.1 makes the 1-1 physical interleave anyway with the Vulcan I/O acceleration code. A/UX 1.0 may not be optimal with 1 & 1; it's possible that some interleaving of filesystem blocks makes sense, but I haven't tried it. I think it's better to make the file system "right" so that it isn't horrible after an upgrade. BTW, mkfs divides the "gap" value by 2 to get 512-byte blocks. That makes a gap of 1-3 become 1; 4-5 become 2; 6-8 become 3, etc. Even dumber. In conclusion, just use 1 & 1 for "gap" and "blocks/cyl". This even improves floppy performance by >2x. -- Rick Auricchio, Apple Computer Inc, 20525 Mariani Av MS 27AJ Cupertino CA 95014 sun!apple!rick OR rick@apple.COM Malibu N4364D (408) 974-4227 People who think money can't buy happiness are shopping in the wrong places. My opinion is my own. My employer? They use a windsock and a fire extinguisher.
dwells@Apple.COM (Dave Wells) (05/25/89)
In article <31426@apple.Apple.COM> rick@apple.com (Rick Auricchio) writes: >Just a quick note on what to use for the mkfs parameters for "gap" and >"blocks/cyl". Use 1 and 1. > >My tests have verified the observation that things are markedly slowed down >by the bogus defaults of 7 and 400. I'm now changing those defaults to 1 and 1 >for a future (post-1.1) release. > >Use of 1 & 1 works fine on the drives I have here; Quantums have partial and >full-track buffering, hence they work well at 1-1 interleave. Seagates don't >have onboard buffering, but A/UX 1.1 makes the 1-1 physical interleave anyway >with the Vulcan I/O acceleration code. Hello Rick, I got your link and saw your posting on the subject. Just thought I'd add my 2 cents. It's also important to remember about physical interleave when preparing a drive for A/UX. Most drives (any I can think of) that provide even partial track buffering will work great at a 1:1 interleave. Unfortunately, not all do provide this buffering. Our own HD 20 SC performs best at 2:1 with a mkfs gap of 1. Format it with a 1:1 interleave and you'll nearly halve the performance. Ouch. Of course, our HD SC setup program almost forces a 1:1 interleave when 'initializing' on a MacII series. You have to go through the cmd-I trick to use anything else. Yep, customers have asked me for the optimal settings for this drive and A/UX. I spent plenty of time playing around with whatever drives I could dig up - That's how I came up with 2:1 for this one. Other low-performance drives will create the same problem when a 1:1 interleave is used. -Dave -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Dave Wells, Apple Computer, Inc. MS: 37-O (408) 974-5515 Mail: dwells@apple.com or AppleLink d.wells or GEnie D.WELLS These opinions may be nothing more than the ramblings of a fatigued tinkerer -=-=-=-=-=-=-=-=-=-=-=-=- There's one big difference between genius and stupidity. Genius has limits. -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
goldfarb@farbmac.UUCP (Benjamin I. Goldfarb) (05/26/89)
In article <31611@apple.Apple.COM>, dwells@Apple.COM (Dave Wells) writes: > Our own HD 20 SC performs best at 2:1 with a mkfs gap of 1. Format it with > a 1:1 interleave and you'll nearly halve the performance. Ouch. Of course, > our HD SC setup program almost forces a 1:1 interleave when 'initializing' > on a MacII series. You have to go through the cmd-I trick to use anything > else. > > Yep, customers have asked me for the optimal settings for this drive and > A/UX. I spent plenty of time playing around with whatever drives I could > dig up - That's how I came up with 2:1 for this one. Other low-performance > drives will create the same problem when a 1:1 interleave is used. > > -Dave I have a Quantum Q280 internal 80 meg drive and a Quantum P80S external 80 meg drive. I've formatted them both with 1:1 interleave and I use mkfs gap of 1. On one of the disks (the external), I have a 60 Meg MacOS partition in addition to A/UX data. Here's the question: if I accept Dave's advice and reformat both drives with 2:1 interleave, will I decrease performance when using MacOS? I assume the answer is yes or Apple wouldn't recommend 1:1 interleave for Mac IIs. If that is the case, is what I have now a reasonable compromise? Or would it be better to leave the outboard drive as is and just reformat the internal? Optimization of mkfs m and n parameters has been a black art ever since mkfs was born. In the ten years or so I've been associated with UNIX I've never developed a firm grasp on this phase of performance tuning. Certainly the discussions on Usenet through the years have shown that the empirical method still reigns supreme in determining m and n. I doubt that things in this area will change toward a pat solution anytime in the near future, given the combinatorial possibilities with drive characteristics, file system organizations, processors, and the many other factors that influence file system performance. ------------------------------------------------------------------------------ Ben Goldfarb uucp: {decvax,peora}!ucf-cs!farbmac!goldfarb Department of Computer Science Internet: goldfarb%farbmac.uucp@ucf-cs.ucf.edu University of Central Florida BITNET: GOLDFARB@UCF1VM ------------------------------------------------------------------------------
dwells@Apple.COM (Dave Wells) (05/31/89)
In article <182@farbmac.UUCP> goldfarb@farbmac.UUCP (Benjamin I. Goldfarb) writes: >In article <31611@apple.Apple.COM>, dwells@Apple.COM (Dave Wells) writes: >> Our own HD 20 SC performs best at 2:1 with a mkfs gap of 1. Format it with >> a 1:1 interleave and you'll nearly halve the performance. Ouch. Of course, >> our HD SC setup program almost forces a 1:1 interleave when 'initializing' >> on a MacII series. You have to go through the cmd-I trick to use anything >> else. >> >> Yep, customers have asked me for the optimal settings for this drive and >> A/UX. I spent plenty of time playing around with whatever drives I could >> dig up - That's how I came up with 2:1 for this one. Other low-performance >> drives will create the same problem when a 1:1 interleave is used. > >I have a Quantum Q280 internal 80 meg drive and a Quantum P80S external 80 >meg drive. I've formatted them both with 1:1 interleave and I use mkfs gap >of 1. On one of the disks (the external), I have a 60 Meg MacOS partition >in addition to A/UX data. >Here's the question: if I accept Dave's advice and reformat both drives >with 2:1 interleave, will I decrease performance when using MacOS? I assume >the answer is yes or Apple wouldn't recommend 1:1 interleave for Mac IIs. >If that is the case, is what I have now a reasonable compromise? Or would >it be better to leave the outboard drive as is and just reformat the internal? Both of the Quantum drives you have should perform best with a 1:1 interleave as I think they both have at least partial track buffering. When I recommended 2:1 for the interleave, I meant only for drives without this buffering. If you reformatted your drives with 2:1 Mac OS and A/UX performance would suffer. You're right about drive configuration being somewhat of a black art. And I agree with you. It probably won't get much better anytime soon. -Dave -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Dave Wells, Apple Computer, Inc. MS: 37-O (408) 974-5515 Mail: dwells@apple.com or AppleLink d.wells or GEnie D.WELLS These opinions may be nothing more than the ramblings of a fatigued tinkerer -=-=-=-=-=-=-=-=-=-=-=-=- There's one big difference between genius and stupidity. Genius has limits. -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-