dhom@cosmos.acs.calpoly.edu (David Hom) (08/18/89)
Remember SCSI Hacker, the program that allowed you to set your interleave on a hard disk to optimize it for the I/O speed of the GS... ***BOTTOM LINE*** IS THERE ANY WAY TO FORMAT A SCSI DRIVE UNDER SYSTEM SOFTWARE 5.0 TO SOMETHING OTHER THAN 1:1 or 2:1 TO TRY TO INCREASE I/O SPEED? Here's the story... I first did a low level format with SCSI Hacker. Then, I ran HDPartition to write a device partition map. I then booted into the finder and a dialog box asking me whether or not I wanted to format my SCSI drive appeared. I answered yes (knowing that with System Software 4.0 when the finder detected a DPM, it did only a High level (OS) format. System software 5.0 has the facility to choose an interleave of 1:1 or 2:1 for SCSI drives so I chose 1:1 thinking it would realize the drive already had a valid DPM. When I clicked format, the finder did a low level format, completely obliterating my previous interleave. I repeated the lowlevel format and DPM creation and tried to format from the finder and ADU. The Finder and ADU ignored the DPM and proceeded with a lowlevel format. There's the story. Thanks for any help. David dhom@cosmos.acs.calpoly.edu
mattd@Apple.COM (Matt Deatherage) (08/19/89)
In article <13662@polyslo.CalPoly.EDU> dhom@cosmos.acs.calpoly.edu.UUCP (David Hom) writes: > >I first did a low level format with SCSI Hacker. Then, I ran >HDPartition to write a device partition map. I then booted into >the finder and a dialog box asking me whether or not I wanted >to format my SCSI drive appeared. I answered yes (knowing that >with System Software 4.0 when the finder detected a DPM, it did >only a High level (OS) format. System software 5.0 has the >facility to choose an interleave of 1:1 or 2:1 for SCSI drives >so I chose 1:1 thinking it would realize the drive already had >a valid DPM. When I clicked format, the finder did a low level >format, completely obliterating my previous interleave. > >I repeated the lowlevel format and DPM creation and tried to format >from the finder and ADU. The Finder and ADU ignored the DPM and >proceeded with a lowlevel format. > >dhom@cosmos.acs.calpoly.edu It's an interesting story, but the conclusions aren't quite correct. "Finder" and "ADU" don't make any assumptions of any kind when formatting devices, nor should any other program. Any call to "Format", the GS/OS System Call, is eventually passed through to the driver, which operates on it how it sees fit. The 4.0 SCSI.DRIVER may, as you said, not actually low-level format the drive on a Format request if it finds a valid DPM. The 5.0 SCSI HD Driver probably thinks "formatting is formatting" and when asked to Format a disk, formats it. (The limited interleave choice is due to the SCSI spec. It notes that 1:1 interleave is standard and any others are device-specific. This "device- specific" interleave can't be identified from software. For Apple's drives, it's 2:1, so that's how it shows up in the dialogs. At least that's how I understand it, but my understanding is a bit murky.) If you've already low-level formatted the drive, it probably doesn't have a file system on it. To put the ProDOS file system on it, you can do one of several things: After low-level formatting, use ProSEL's (or anybody's) "Erase Disk" function. If you're a developer or have access to the GS/OS Exerciser, go in and make the EraseDisk call to the SCSI Drive's device number yourself. This will put a file system on it without reformatting it, and then the Finder or any other program should have no problems with it. ----------------------------------------------------------------------------- Matt Deatherage, Apple Computer, Inc. | "The opinions expressed in this tome Send PERSONAL mail ONLY (please) to: | should not be construed to imply that AppleLink PE: Matt DTS GEnie: AIIDTS | Apple Computer, Inc., or any of its CompuServe: 76703,3030 | subsidiaries, in whole or in part, Usenet: mattd@apple.com | have any opinion on any subject." UUCP: (other stuff)!ames!apple!mattd | "So there." -----------------------------------------------------------------------------