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Delphi Mac Digest Saturday, 4 October 1986 Volume 2 : Issue 49 Today's Topics: 2 MB + RAMSafe = Heaven (3 messages) Uses of Memory (8 messages) Report on TML Pascal 2.0 (4 messages) Line Conditioners/AC power (7 messages) MonsterMac/Switcher ? (2 messages) floating pt boards another 800K dies RE: User Interface Problem: Macintosh Alert Boxes Re: Misc. programming problems ----------------------------------------------------------------------- From: IVANOVIC (13325) Subject: 2 MB + RAMSafe = Heaven Date: 2-OCT-01:47: Programming 2 MB + RAMSafe = Heaven I just got a Levco MonsterMac clip-on upgrade to my 512E with RAMSafe*, bringing it to 2MB. RAMSafe is a RAM disk that doesn't go away when the system crashes. It consists of two PROMs that fit on the Levco board and an installation/configuration program. The way it works is the PROMs snatch the signal that resets memory from the jaws of death, turning the electrons into sweet smelling ether. Voila! your RAM disk doesn't go away when your system bombs. Turning the power off though is more karma than the PROMs can deal with, though, and that will do the RAM disk in. The RAM disk is configurable from 512K to 1.5MB in 256K increments. It is HFS. I've had some problems with the upgrade (system won't come back after a power off) but I think that's due to the upgrade altering the power supply voltage rather than RAMSafe. The seller, K.B. Company of Boston has been quite helpful. They extend Levco's warranty to 120 days from 90 days and also warrant the original motherboard for the same time. The clip-on Levco board (if removed before an Apple dealer sees it!) won't void the AppleCare warranty. RAMSafe itself works well. The system reboots in 6 seconds and that includes installation of a 73KB TMON. Just for fun, I ran DiskBench on the RAM disk and got 2.42 seconds (145-146 ticks) for 100 32KB reads or writes, and 0.07 seconds (4 ticks) for 80 1MB seeks. Wow! Rebooting is so fast it's hard to turn the Mac off before the welcome message comes on unless you've got your finger on the on-off switch already. I like that! If the rumors that Apple is going to come out with a 8MB SCSI RAM disk are correct, they have one hot product. I can't wait, though I probably can't afford it. While on the subject of disk performance, I'd like to observe that according to studies done by Digital Equipment Corp., the contribution that the transfer rate of a disk makes to overall, perceived performance is way overshadowed by that of access or seek times. Since most disk accesses are for a small number of blocks, the time spent transferring the data is small compared to preparing to transfer the data, i.e. the seek times. (At 330KB/s a 2048 byte transfer takes 6 ms. Average seek times are 65-85 ms, depending on the drive.) Go for the faster access times, unless you've got a specialized application like real-time data collection. Hence, therefore, ergo, the XP upgrade to the DataFrame 20 is in all likelihood a $99 (?) donation to SuperMac Technology. Now they're deserving people and all that, but it won't do squat for performance you'll see. And oh, BTW, what's the meaning of DiskBench's "1 MB seek"? To me, a seek is the drive's process of setting up for a transfer. There is no data size associated with it. P.S. I don't keep anything in the RAM disk I'm not prepared to lose. I have faith, but I also have experience! Save early and save often, to paraphrase Mayor Daley. Update on the upgrade/RAMSafe saga. KB Co. replaced my mother board and adjusted the voltage to exactly 5.00 volts. I haven't had any crashes and the system reboots fine. I hope the problem has been licked. * RAMSafe is a trademark of somebody or other. (They got the first part right: put the letters "tm" after the trademark; but somewhere you gotta say who owns the trademark!) RAMSafe is distributed by CJS Systems, 3051 Adeline, Suite 1, Berkeley, CA 94703. (415) 849-3730. It was written by Paul Mercer. I assume that Levco will sell it to you also. I got mine through the local Levco dealer, K.B. Company in Boston. -- Vladimir ------------------------------ From: BRECHER (13335) Subject: RE: 2 MB + RAMSafe = Heaven (Re: Msg 13325) Date: 2-OCT-08:16: Programming DEC's studies most likely used DEC's operating systems -- almost certainly multi-user. No doubt that access time is important, though. DiskTimer's "1MB seek" is a seek across 1MB of disk capacity. The test consists of reading 1 sector at/near the beginning of the volume and then 1 sector at an offset of 1MB from the first read (this process done 80 times). ------------------------------ From: MACINTOUCH (13342) Subject: RE: 2 MB + RAMSafe = Heaven (Re: Msg 13335) Date: 2-OCT-17:18: Programming Just a note on recoverable RAM disks. The one in the HyperDrive 2000 also sticks around until you power off. I don't know how they do it, but I don't think Paul had anything to do with it <grin>. Ric ------------------------------ From: IVANOVIC (13326) Subject: Uses of Memory Date: 2-OCT-01:48: Programming On the Uses of Memory and Other Important Matters With a bountiful supply, I started to think about the best way to use the 2MB I now have. I started experimenting, and the first configuration I came up with was 512K for the RAM disk and several Switcher partitions. I run with TMON and Tempo but without the disk cache. Well, folks, that doesn't work. The menus end up with non-ASCII junk in them, even though switching around seems to clear things up, why I don't know. Anyway, why keep a program on RAM disk AND in Switcher-controlled memory! Talk about double-buffering! After several changes, the configuration I currently have is a 1MB RAM disk, a 73MB TMON installed in high memory before Tempo gets started and no Switcher. The RAM disk contains the System Folder and an application with its supporting executables (e.g. TML Pascal, Edit, Linker and RMover, or LightspeedC). All modifiable data files are on either a 800K internal floppy or an external 400K floppy. (My hard disk is on order.) I've now reduced the number of system bombs to what they were after I upgraded to the 128K ROMs, but still very much higher than with the 64K ROMs. Has anyone else noticed the increase in frequency of bombs with the 128K ROMs? (I use System 3.2 and Finder 5.3 but no HD20.) I suppose I ought to keep track of what the bombs are... but there are so many of them! Should it be possible to have a RAM disk, TMON or Macsbug, Tempo, and a disk cache on, plus several Switcher partitions all at the same time? (All these guys do funky things with memory.) It's really not that farfetched. I'm almost there. With the imminent installation of a hard disk, I'll soon want a disk cache. With the rumored 8MB SCSI RAM disk, I'll definitively want many Switcher partitions. And I want to be able to run a debugger also. Tempo saves time. With the current state of affairs, I don't think it is possible to expect that all those programs will work flawlessly together. Didn't the IBM PC folks just go through a "learning experience" just like the one we're about to what with all their RAM-resident pop-up applications? What lessons did they learn? -- Vladimir ------------------------------ From: PEABO (13337) Subject: RE: Uses of Memory (Re: Msg 13326) Date: 2-OCT-12:02: Programming I don't see why a properly installed RAMdisk should interfere with other -high- memory-resident products like TMON. As a basis of comparison, you probably should try RAMStart. Version 1.23 is in the database now, and I have a -version 1.3 which should be in the database here this weekend. The SCSI RAMdisk is external and therefore (if it exists) will not have -nearly as good performance as a RAMdisk composed of addressible memory. Your point about reduced seek time is well taken though. peter ------------------------------ From: MACINTOUCH (13343) Subject: RE: Uses of Memory (Re: Msg 13337) Date: 2-OCT-17:20: Programming The TurboCharger 2.0 disk cache lets you select which disks to cache, so that you can avoid "double buffering" situations. Ric ------------------------------ From: IVANOVIC (13350) Subject: RE: Uses of Memory (Re: Msg 13343) Date: 2-OCT-21:21: Programming I was curious about TurboCharger 2.0. Do you use it? Pros, cons? The slim amount of information that I have come across seems to indicate that it's the most sophisticated of the lot. With statistics gathering ability, it ought -to perform the best. -- Vladimir ------------------------------ From: MACINTOUCH (13356) Subject: RE: Uses of Memory (Re: Msg 13350) Date: 2-OCT-21:52: Programming I have a very unstable, changing environment at the moment, after suffering a month without a hard disk and having problems getting upgraded to a Mac Plus, given the HyperDrive and the stuff the dealer is giving me about month-long delays for upgrade kits. (Is that bull?) I like TurboCharger, but don't always use it because of testing of all these different hardware and software configurations. If I had a standard Mac Plus and one hard drive, I'd seriously consider it after checking the TOPS compatibility. Ric ------------------------------ From: IVANOVIC (13358) Subject: RE: Uses of Memory (Re: Msg 13337) Date: 2-OCT-21:58: Programming In addition to "properly installed" one should add "properly written." I -hope none of the authors have resorted to "tricks" which are System version dependent. I just remembered that TMON has a "Launch..." menu item. I now know how to -use RAMSafe, Switcher and TMON all at once. -- Vladimir ------------------------------ From: IVANOVIC (13370) Subject: RE: Uses of Memory (Re: Msg 13358) Date: 2-OCT-23:30: Programming Well, _I_ can't get RAMSafe, Switcher and TMON all to work. I can get as far -as launching TMON in a Switcher partition, butall goes to pot as oon as I try to launch an application under TMON. Maybe I should try the system heap... -- Vladimir ------------------------------ From: DWB (13390) Subject: RE: Uses of Memory (Re: Msg 13370) Date: 3-OCT-01:28: Programming You will definitely have to load all memory resident stuff (TMon, RamDisk Disk Cache, etc.) into memory before running switcher. Switcher won't cooperate well with applications which change the size of memory after it gets started. To take message 13387 one step further, I have actually used a configuration of TMon, RamStart 1.24, and Switcher at the same time. It worked quite well. RamSafe may not play by the rules but I would be extremely suprised to find that it doesn't. David ------------------------------ From: IVANOVIC (13327) Subject: Report on TML Pascal 2.0 Date: 2-OCT-01:49: Programming Report on TML Pascal v2.0 I am posting this message to Delphi rather than privately to Tom Leonard because last time I did so (version 1.2), it had no effect. Tom didn't bother to reply ("Yes, I got the bug report, thanks." was all I was looking for) and he didn't correct the bugs I submitted. Notes "ANSI Pascal" refers to the ANSI/IEEE X3.97-1983 definition of Pascal. "ISO Pascal" refers to the ISO dp7185 defininition of Pascal. Level 0 of ISO Pascal is equivalent to ANSI Pascal. Level 1 of ISO Pascal incorporates conformant array parameters over Level 0. The "User's Guide" refers to the TML Pascal Users's Guide v2.0 of August 1986. The "Reference Manual" refers to the TML Pascal Reference Manual, v2.0 of August 1986. Omissions There is NO statement in either the Users's Guide or in the Reference Manual of compatibility with anything. In the User's Guide, p. 1-2, Jensen and Wirth (3rd ed.), ANSI/IEEE Standard 770 and Henry Legard's annotations are listed as "good references to the Pascal language itself." What does this mean? Is TML Pascal intended to be compatible with ANSI or with ISO Pascal? A superset of either of them? The Macintosh Pascal Reference Manual states in line 1 of the Preface (!) what these documents are (descriptions of the language supported by Macintosh Pascal) and in line 2 that this language is intended to be ANSI Pascal compatible. What is TML's equivalent statement? Procedural and functional parameters (noted as an Implementation Note) are not supported. This is Level 0 stuff! When is it going to get supported? No error numbers are listed with the errors reported in Appendix A, Section 2 of the Reference Manual. Why list them at all? How about a suggested course of action for each error message? The non-terminal "sign" is never defined in the Reference Manual. The file MacIntf.pas is incomplete. In particular, a number of I/O completion codes are missing, namely -1 to -32. There are also others. The compiler's version numbers does not appear in the listing file. The linker's version number does not appear in the map file. The file "Boot Paths" with a system icon does not have any documentation. Does anyone know what it does? Note: it's not the "Paths File". Errors The compiler reports an error without any message. The error number is 105. The compiler reports errors when given the text: PROGRAM subrange_errors; CONST a = 15; { (2**4) - 1 } b = 255; { (2**8) - 1 } c = 32767; { (2**16) - 1 = maxint } d = 2147483647; { (2**32) - 1 = maxlongint } TYPE a_type = -a..+a; b_type = -b..+b; c1_type = -c..+c; c2_type = -maxint..+maxint; d1_type = -d..+d; d2_type = -maxlongint..+maxlongint; BEGIN END. Errors (# 105) are incorrectly reported for a_type, b_type and both c_types. No errors are reported for either d_types. The d_types are permitted by TML Pascal but are NOT ANSI Pascal. Macintosh Pascal v2.0 compiles the above program but flags the d_types as illegal. The compiler reports errors when given the text: PROGRAM goto_errors; LABEL 1, 10001; VAR x : integer; PROCEDURE a; BEGIN GOTO 10001; END; PROCEDURE b; BEGIN GOTO 1; END; BEGIN a; 10001: b; 1: x := 0; END. ANSI Pascal says that 10001 is an illegal label. The Reference Manual implies that labels can have values up to maxint. Both the GOTOs should compile. The compiler flags them as being an implementation restriction. No such restriction is noted in the Reference Manual. Macintosh Pascal v2.0 flags 10001 as illegal and compiles the rest. When the /Code option of the linker is selected, there appears at the end of those procedures which define strings, code without the usual addresses to the left, but, with instead, 5 characters (in hex: 4E BA FE 80 3C) unrelated to either the address or to the string. The code for the strings is presumably correct. The listing of the addresses continues correctly in the next module. What are these characters? Typos "Miscellaneous" is misspelled in the Table of Contents of the Reference Manual. Pages A-4, A-3 and A-2 of the Reference Manual are out of order. Suggestions Have a standard/no standard option for the compiler. VAX-11 Pascal compiles anything the manual describes, including DEC extensions, but will flag as non-portable, optionionally, those extension it finds. Have an option to turn off optimization. Sophisticated debuggers get confused by optimization. Provide a symbolic, source code debugger. Provide a symbolic, source code debugger. Provide a symbolic, source code debugger. Get the hint? Enough information should appear in the listing and map files to recreate the identical compilation or linking scenario. In other words, the listing file should also list the options used, the date and time and the system version number. The linker should reproduce the .Link input file along with the system version number, its version number and the date and time. It should be possible to create a file that contains the following information: The source line. The corresponding assembly code. The corresponding object code. I am very close to the point of abandoning TML Systems. I need a Pascal that will compile standard ANSI (at least, and better yet ISO Level 1) Pascal. TML Pascal doesn't do it. I assume (and will check out BEFORE I buy) that Lightspeed Pascal recognizes the same language as Macintosh Pascal. If so, it's been real TML. LSP has an entire development environment that is fast. Now, if it only supported MacApp... -- Vladimir ------------------------------ From: MACINTOUCH (13344) Subject: RE: Report on TML Pascal 2.0 (Re: Msg 13327) Date: 2-OCT-17:23: Programming Tom has done an astounding amount of work for a one-man company. I'm not surprised to hear he may have dropped the ball once or twice on support. He is online here and on CompuServe, and has an MCI account. It might be worth trying to send a note to him this way. Ric ------------------------------ From: IVANOVIC (13352) Subject: RE: Report on TML Pascal 2.0 (Re: Msg 13344) Date: 2-OCT-21:38: Programming I realize the amount of work he's done alone. The cynic in me says that to compete effectively in the marketplace, he might have to learn to leaverage his knowledge by hiring and working with others. I bought TML Pascal v1.0 because it was the first Pascal for the Macintosh. He's now got powerful competition in MPW Pascal and Lightspeed Pascal. I've added my thoughts on how he can retain me as a user. I will ultimately use the product that best meets my needs. The actual support I was looking for was a very simple response (should be automatic) like, "I've received your bug report," nothing more. I can -usually figure things out myself if the compiler emits assembly language (are you listening LightspeedC people?) I'm more adamant on the issue of standards. Pascal is well-established as -both a national and an international standard. The draft ISO version was -available well before the final version. There's really no excuse for not being up to snuff. I don't want to have to re-write an entire application simply because TML Pascal can't compile ANSI (not even ISO!) standard Pascal. Portability -is important to me - I don't want to re-invent the wheel. I have enough other troubles as it is. -- Vladimir ------------------------------ From: PEABO (13373) Subject: RE: Report on TML Pascal 2.0 (Re: Msg 13327) Date: 2-OCT-23:55: Programming Another reason why it's nice to be able to shut off optimization is that code generators occasionally make gruesome errors while optimizing that they wouldn't make when not optimizing. It's really nice to be able to shut off the optimizer and try running the program again. peter ------------------------------ From: MACINTOUCH (13346) Subject: Line Conditioners/AC power Date: 2-OCT-17:34: Hardware & Peripherals You know how Apple is always saying the LaserWriter is their most powerful computer? Yeah, but it's not because of the 1.5MB of RAM, it's because it sucks up 800 WATTS! This was dimming the lights in our new, old office, and giving us fits about HyperDrive longevity. A UPS (uninterruptible power supply) looked like a good idea, but a good one seemed to cost about $1K. We compromised and got a 300Watt "line conditioner." I thought people might like to know how it worked out. Basically, it cut back the power drops to the point where you can just barely notice a change in light intensity when the LaserWriter cycles -- before, it was like flashes of lightning (almost). The one we got without shopping around was $200. (Rush, rush). One anomaly is that now the light dims momentarily when the Mac is switched on! Anyone got an explanation for this? (Any power engineers in the SIG?) Ric Ford "MacInTouch" ------------------------------ From: MACINTOUCH (13360) Subject: RE: Line Conditioners/AC power (Re: Msg 13346) Date: 2-OCT-22:10: Hardware & Peripherals Following up on a couple of things. The device makes a hum that's mildly annoying. It also get so hot you can't touch it. Anybody know of good UPS's well under $1K that produce sine-wave output, are well-built, and have fast enough switching times? Ric ------------------------------ From: MOUSEKETEER (13362) Subject: RE: Line Conditioners/AC power (Re: Msg 13360) Date: 2-OCT-22:49: Hardware & Peripherals Hi Ric, Ya, UPS's are hefty in price. There is a smaller company somewhere making them up at around $750, but if you dig into the specs, you aren't getting much at that price in terms of switching times, etc. A lot of that $1000 goes into liability insurance...just in case that UPS running the Acme Oxygen Pump cuts out sometime. I'd suggest you give Frank Stifter at Electronic Specialists Inc. a call... he's right up there in Natick, MA near you at 617-655-1532. While they do market a very complete line of UPS and such gear, Frank is great at -talking to you about just what problems are going on, and the best way to handle -them. It's the heater unit in the Laser sucking all the power, and the way it cuts in and out at various times doesn't help matters. I'd be just as concerned about what those wires in the wall are doing while the Laser is hooked up... it can get pretty toasty. Maybe a wall run of plastic conduit and some 12 -ga. directly to the Laser from the junction box would be a safer (and -considerably less expensive) solution (assuming you can bypass local regulations and do -the work yourself...grin). I'm more into overkill. I have 8 separate ciruits in a room 12x17, each set for 30 amps. Some people say that 56 outlets is too many in a single room, but.... Alf ------------------------------ From: DWB (13389) Subject: RE: Line Conditioners/AC power (Re: Msg 13346) Date: 3-OCT-01:24: Hardware & Peripherals About two months ago I went out and bought I UPS at a local discount house (Frye's Electronics for those of you that care) I am quite happy with it. I did have to get a DataFrame though instead of the old clunker I was using (shame that :-) because the clunker died when the power went out. I've now been using my mac a couple of times when we had a power outage and everything kept right on chugging, just like it's supposed to. Even when the power company pulled what is a common trick around here of taking the power out, waiting 30 seconds, and turning it back on for a half second or so. For the number and review freaks amongst you it's a Relax Technologies BPS 1. Works like a champ. David ------------------------------ From: DWB (13391) Subject: RE: Line Conditioners/AC power (Re: Msg 13389) Date: 3-OCT-01:31: Hardware & Peripherals Oh yeah, it cost under $300. David ------------------------------ From: NAKMAN (13400) Subject: RE: Line Conditioners/AC power (Re: Msg 13360) Date: 3-OCT-03:47: Hardware & Peripherals If you need the UPS just for the Mac, check out the article by Jay James in -the Fall 1985 BMUG NL. It describes how to build an uninterruptible power supply for less than $100. It puts out square waves, and can't give much power, and simply involves a battery charger, a car battery, and an inverter, but, hey, -it does the job! -- Raines / Team BMUG ------------------------------ From: JEFFS (13407) Subject: RE: Line Conditioners/AC power (Re: Msg 13402) Date: 3-OCT-18:28: Hardware & Peripherals I have a Topaz Powermaker UPS. I have the 400VA model which lasts 35 minutes under full load and 75 under half. It puts out nice sine wave 60 Hz current for my Mac and all peripherals. It has a 4 millisecond (typical with 10 mill max) switching time. It set me back $800 when I bought it. Jeff ------------------------------ From: ROWLAND (13349) Subject: MonsterMac/Switcher ? Date: 2-OCT-20:39: Business Mac I suddenly started having a problem that puzzles me : switcher stopped -working on my MonsterMac(with 128K ROM). It starts up, draws the box that is to -contain the applications, but doesn't fill anything in. It then hangs - the mouse -works but nothing else does; I have to reboot. Details: Switcher 5.0b3 , Sys/Finder 3.2 : I've replaced both the system file and switcher from virgin copies so I think they are OK. Switcher does work -when I use that copy (and system - but with HD20 file) on a 64K Rom normal Mac. I have used successfully exactly the system that fails (though of course not identical - there was a period of a month or so that I didn't use switcher, -and did the usual changes to things). If there are any suggestions or other experiences, I'd be glad to hear them. -( I'm anxiously waiting for Servant, but till then ..). Thanks Mike Burns ------------------------------ From: HSTARR (13405) Subject: RE: MonsterMac/Switcher ? (Re: Msg 13349) Date: 3-OCT-18:12: Business Mac That behaviour is normally Appletalk opening -- do yuou have Appletalk on in the Control panel?? If you have, and you have anything but an Appletalk pod connected to the printer port -- it is usually Bye,Bye!! ------------------------------ From: RONB (13366) Subject: floating pt boards Date: 2-OCT-23:21: Hardware & Peripherals Does anyone have any experience/information about floating point add-in -boards? I'm particularly interested in speeding up fortran code. (I'm aware of the recent Macworld article). Thanks in advance... Ron. ------------------------------ From: MACINTOUCH (13367) Subject: another 800K dies Date: 2-OCT-23:21: Hardware & Peripherals Another 800K internal drive just croaked without warning. It won't read or initialize any disks successfully. On the _other_ Mac, today, a disk got -stuck in the internal 800K drive. No extra labels, no obvious problems, but it wouldn't come out except with a paper-clip boost (gives you that cold sweat feeling ...). It may have been a C Itoh disk, as it was dark red. Ric ------------------------------ From: PEABO (13378) Subject: RE: User Interface Problem: Macintosh Alert Boxes Date: 3-OCT-00:30: Network Digests >Date: Wed, 1 Oct 86 13:42:52 PDT >From: <DAVEG@SLACVM.BITNET> >Reply-to: DAVEG%SLACVM.BITNET@Forsythe.Stanford.Edu >Subject: User Interface Problem: Macintosh Alert Boxes >I've had a gripe about the Mac user interface for quite a while. The -specific >problem is alert boxes which only have an OK button. These boxes are -typically >used to warn the user that something has gone wrong during the processing >of some request by the user. A good example is the Finder. You drag >6 folders from one disk to another and go off to do something else while >the Mac is busy doing the copying. You return 1/2 hour later assuming that >the files have been copied, only to find that there is an ALERT box on >the screen which says " The file DAVEG.GOODIES cannot be written" or -something >to that effect. Not only that, but suppose you are sitting there watching the Finder copy a selection of files, and you get several of these alerts (this has happened to me on more than one occasion). What are you supposed to do, write down the names of the files??? (1) I got a computer so I wouldn't have to use paper and pencil anymore (ha!) and (2) under HFS, writing down file names can be pretty tedious. It seems to me that what is needed at least in this specific case is a notion of a task composed of a number of subsidiary tasks, which can be completed independently, and for which at the end there is some summary of results, such as a list of files that didn't make it. You might ask for example to select all files that appear in the list, or just scroll through them. Another gripe of mine is what happens when I select a random subset of files in a folder to copy somewhere. After the Finder is done, the files I copied are no longer selected, so I have to go though and select them again, should I want to throw them in the trash for example. Hope I -don't make a mistake! I'm not sure what the Finder should do in this case (I don't remember either, which may be because my idea of the right thing is to keep the files selected for another operation). Perhaps what it does now is dictated by some other user interface principle that doesn't come to mind at the moment. It may -boil down to a limitation in understanding what the intent of the user is when performing a sequence of operations on a bunch of items. The more -assumptions a program makes about what the user probably intends, the more the program is suffering from modal operation. peter ------------------------------ From: BRECHER (13393) Subject: Re: Misc. programming problems Date: 3-OCT-01:53: MUGS Online To: Mark Nodine <mnodine@labs-b.bbn.com> Subject: Misc. programming problems > ... if you call SetVol with the number returned as the volume reference > number by SFGetFile, it returns an error that there is no such volume. This should work. Perhaps you are not clearing the ioNamePtr field of the parameter block? ioNamePtr takes precedence over ioVRefNum, so if you have garbage in ioNamePtr it will fail. If you're using the high level SetVol rather than PBSetVol, you should pass Nil for the StringPtr argument (do not pass a pointer to a zero-length string). ------------------------------