Path: utzoo!utgpu!watserv1!watmath!att!pacbell!pacbell.com!decwrl!csus.edu!ucdavis!csusac!csuchico.edu!mrush From: mrush@csuchico.edu (Matt "C P." Rush) Newsgroups: comp.sys.amiga.hardware Subject: Re: Obsessive Multitasking and Amiga File I/O Scheduling Message-ID: <1990Sep08.210559.19597@ecst.csuchico.edu> Date: 8 Sep 90 21:05:59 GMT References: <6499@sugar.hackercorp.com> <1159@mpirbn.mpifr-bonn.mpg.de> <14260@cbmvax.commodore.com> <1990Sep8.050725.14384@zorch.SF-Bay.ORG> Sender: news@ecst.csuchico.edu (USENET) Reply-To: mrush@cscihp.UUCP Organization: California State University, Chico Lines: 88 In article <1990Sep8.050725.14384@zorch.SF-Bay.ORG> xanthian@zorch.SF-Bay.ORG (Kent Paul Dolan) writes: >jesup@cbmvax (Randell Jesup) writes: > >I didn't think my use patterns were that unusual, but maybe so. > >Yesterday, in a fairly typical setup, I had half a dozen shells open on >the (A2000,1.3) workbench, doing various combinations of zoo -add, >zoo -extract, lharc a, lharc x, interactive dir-s and info-s and list-s >to make sure I wasn't clobbering Rad:, and on another screen, vt100 >running to do downloads. > >Slow as molasses, on a 68000, but productive as heck, since I could read >news and mail between downloads, and just flip back to the workbench >every once in a while to get a new process going in the next window. Sounds like the sort of thing I do, though I'm running a 68010. >I bought my first Amiga, and this latest one, to *multitask*, and I spend >lots of days like the above. Of course, poverty and indolence keep me >running out of Rad:, but I'm really upset to find out that a machine >whose internal OS is multitasking all the way has such uneven/unbalanced >support for it overall that I'd be really unhappy trying to do the same >thing from a hard disk. Multitasking was EXACTLY the reason I bought my first Amiga, and I haven't had that much trouble thrashing disks. Sure, if you have multiple tasks that are accessing different cylinders on the same floppy there's going to be some head movement. But that's why Amiga floppies have that extra little circuit board that PC floppies don't have -- so the drives can be individually controlled! If you don't wanna bang your heads around, get a second (or third, or fourth) floppy. Or as you're doing, use a ram disk. As far as this sort of thing goes on a Hard Disk, it's just fine. I do all my multitasking from my ST157-N running on a Pacific Peripherals DMA 'OverDrive' controller with no problems. On the occasions where I know I'm going to be doing a lot of disk thrashing I use the ol' AddBuffers command. That's what it's there for! >Is there a better disk I/O scheduling algorithm in 2.0, or at least one >in work? As Randall notes, the solutions are well known, and should be >"in there" by now. It's been over five years, after all. > >Along with the deadly repeated "key error, backup, reformat and reload" >problems reported here so often, this is another market killer for the >business marketplace (which surely won't tolerate the unreliable hard >disk problem like a crowd of hackers/students ready to do the "repairs" >themselves will), and both need fixes Really Soon. > >Buying a machine that advertises multitasking, and then hearing your >disk drive attempt to self destruct when you try to do so is almost >as unimpressive as having your _whole_ file system go gaga and need a >long, frustrating recovery to be done, every time a program dies in >mid-write. Fsck is overdue for AmigaDOS. I don't think CBM can be held responsible for Hard Disks that get trashed because of programs failing during Writing. This is more the responsibility of the companies that manufacture the Hard Drive controllers and associated drivers. I used to trash (error validating, key not found) my old Xebec 9720H on my A1000 almost everytime I did an icon snapshot. This wasn't any fault with the OS, it was that Xebec didn't know how to program for a multitasking environment and used a lot of busy waits for timing. My current hard drive on my A2000 has never gotten trashed in over three years -- even if I try! >So tell me, am I the only one multitasking this sucker within an inch of >its life as a regular way of doing work? Or is this the general problem >I perceive it to be? No, on both accounts. It is a problem of PC developers using PC techniques on the Amiga, in total disregard of everything that CBM has warned against since the 1.0 RKM's. Of course my Operating Systems Programming instructor would say that this is not true multitasking because the Amiga doesn't have an MMU. But that instructor was a dweeb. -- Matt *~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~* % "Progress is an up-hill battle % mrush@csuchico.edu % % against backwards compatibility." % mrush@cscihp.UUCP % % -- me % % Now: mrush@cscihp.ecst.csuchico.edu % *~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~* This is a SCHOOL! Do you think they even CARE about MY opinions?!