Questions and Answers
Copyright (c) 1995 Apple Users' Group, Sydney
Republished from Applecations, a publication of the Apple Users' Group, Sydney, Australia.
Source: internet comp.sys.apple2
Q: How many devices can I hook up to my SCSI card?
A: The SCSI standard supports up to eight devices in a chain. Each device in the chain needs a unique SCSI ID. Some SCSI cards use a SCSI ID for themselves (e.g. Apple Rev C SCSI and Apple Hi Speed SCSI) and therefore can be selected by external devices. These cards can support seven other devices.
Other cards (e.g. RamFAST) do not use a SCSI ID so they can support eight devices.
Q: I recently bought some 5.25" HD disks for use on my Apple IIe because there weren't any of the cheaper DD variety available. However, they would not format. Why not?
A: Computer discs are nothing more than flat plastic discs with a layer of magnetic stuff on them. But, different types of drives need different properties in the magnetic layer: from what I remember, I think higher density disks (1.2MB) disks need media with a much higher flux. So, the disks may look the same, but they behave rather differently in your drive.
Q: I recently picked up an Apple IIgs which doesn't say ROM 01 or ROM 3 and it has "Woz Limited Edition" on the front. Is this a ROM 00 machine? If so, what exactly do I need to upgrade?
A: The "Woz Limited Edition" machines were all ROM 00. Most will have been upgraded to ROM 01. Of course, it is possible that the lid or motherboard has been swapped with another machine.
The ROM version message is displayed on the first screen after the computer starts up (text mode, "Apple IIgs" at the top), the ROM 00 has the rest of the screen blank. ROM 01 and ROM 3 have a copyright message and ROM version indication at the bottom of the screen.
You need the version 01 ROM which should be available as a free upgrade from an Apple dealer. It is a simple chip swap.
Depending on which production run your machine comes from, you might also need an updated VGC (Video Graphics Controller). If you have a colour monitor, the best way to check for this is to run a program that uses Double hi-res graphics in monochrome mode. The original IIgs System Disk with MouseDesk (System 1.0 through 2.0) is probably easiest. A faulty VGC will display the MouseDesk desktop in grey and pink, with strange pink fringing effects. A correct VGC will display the desktop in grey only.
Some faulty VGCs will also display pink or flickering fringing in 80-column text mode, which varies according to the foreground and background colours you've selected.
The VGC should also be available as a free update from an Apple
dealer. It is just a chip swap, but it is a socketed PLCC chip, so it
needs a special tool to remove the old VGC.
If you cannot get this chip from an Apple dealer, Alltech Electronics
may be able to supply one, but it will cost you something.
Q: Is the "Woz Limited Edition" Apple IIgs really a limited edition?
A: Not really - the first few thousand cases have "Woz Limited Edition" printed on them. The machines are identical apart from that. I've seen guesstimates ranging from the first 10,000 IIgses to the first 100,000. The only significance is sentimental value, and I doubt anyone would pay more to get a "limited edition" machine.
Q: Can I use the Apple IIgs 12" RGB monitor with my Mac?
A: No. The IIgs monitor has a lower scan rate than the Mac monitor. You cannot use Mac monitors on the IIgs or the IIgs monitor on a Mac. Some third-party multisync monitors with a wide range of sync frequencies may work on both machines.
Q: Can I use the Apple II mouse with my Mac (my Mac mouse is dying)?
A: The IIgs mouse is identical to the Apple Desktop Bus used on the Mac SE, Mac II and later machines. It is not compatible with the Mac 128, 512, 512KE or Plus. These machines use the same mouse as the Apple IIe or IIc.
You can also interchange most Apple Desktop Bus keyboards between the Apple IIgs and Macintosh. The main exception is the ergonomic keyboard, which doesn't work properly on the IIgs.
You cannot connect the keyboard and/or mouse to both machines at the same time. You should power off the machine before attaching or removing the keyboard or mouse.
Q: I found an error in the ORCA Window Manager interface file. The DoModalWindow call is passing the event record by value, not as a pointer. You need to edit the WindowMgr.pas file (in the Tool.Interface directory, which you may not have installed from the distribution disks), and change the first parameter of DoModalWindow to a 'var', then recompile it and copy WindowMgr.int to 13/ORCAPascalDefs.
A: This is really interesting. I've been using the DoModalWindow call successfully in my programs, and I checked the definition in the Window Manager interface file in ORCA/Pascal. The definition does show the event record as a value parameter, which should cause problems, but in practice it works fine. Here's why:
In the ORCA/Pascal manual, in the chapter about interfacing to assembly language subroutines, the parameter passing mechanism is described. For simple variables (boolean, integer, real, longint), the value of the variable is pushed on the stack. However, for longer structures (arrays, records), a pointer to the structure is pushed on the stack. Yes, a pointer! So, since the event record variable is defined (in the Common unit) as a record, ORCA/Pascal actually pushed the pointer to the structure, (even though it is a value parameter in the definition) and DoModalWindow is happy.
Q: I have heard that the maximum amount of memory I can have is 8 megs, but what of adding 8 megs to the 1.125 megs already in the ROM 3? How much of that RAM would be DMA compatible?
A: If you put an 8MB RAM card into a ROM 3, only 7MB of it can be accessed. In a ROM 1, only 7.875MB of the card can be accessed. The maximum amount of RAM supported by any version of the IIgs is 8 megabytes of fast RAM plus 128k of slow RAM, for a total of 8.125MB.
In the ROM 1, 4.125MB of fast RAM is DMA compatible. In the ROM 3, 5MB of fast RAM is DMA compatible. In both cases, this is the RAM installed on the motherboard plus 4MB from the memory expansion card. This assumes the card is DMA compatible. Most cards that support more than 4MB are not DMA compatible.
Q: Why is it that the GS can handle 16 megs of addresses, but only 8 megs can be used? What happens to the other 8 megs of space?
A: 8MB for fast RAM, 1MB for ROM, plus 128k for slow RAM. There is a large unused region in banks $80-$DF, and in banks $E2-$EF. If a memory card tried to support the other 8MB, the IIgs Memory Manager wouldn't know about it unless it was patched.
Q: I read in the IIgs Tech. Introduction that IIe Ram expansion
cards work with the IIgs but System 6.0 doesn't find it. What's happening?
A: Cards designed for the auxiliary slot do not work on the IIGS, but normal memory cards 'work', but they don't do what you might think they do. AppleWorks will see the memory, as well as a number of other 8-bit applications. You can use the card as a RAMdisk in GS/OS; that's what the RAM driver is for. However, the memory does not show up as 'main' memory. For that, you must use the IIGS's memory expansion slot with a card for it.
Q: I've noticed in the "About this Apple IIGS" selection under the Apple Menu, that my memory allocation for Desk Accessories is nearly 2325K RAM when in fact, I've only got slightly under 200K used for DAs (I checked by opening my DA folder). What gives?
A: Include all the Control Panels (in the CDEVS folder) in your calculation for memory usage, and in particular, all the sounds you have attached to events in the Sound control panel. All of these sounds are loaded into memory at boot time (or when you change the assignments in the Sound control panel).
Longer sounds need more memory, as do sounds that were digitised at a higher speed. The standard recording speed used by the Mac (11 kilosamples per second) requires 11000 bytes for each second of sound. Common higher recording speeds are 22 kilosamples per second (22000 bytes per second) and 44 kilosamples per second (44000 bytes per second).
Also note that the amount of memory required by a program may be quite different to the size of the file on disk. It may allocate extra memory once loaded, for example.
Most IIgs programs that don't allocate extra memory will be smaller in memory than on disk, because the disk representation includes headers and relocation information, which is not required once the program has been loaded.

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