Questions and Answers
Copyright (c) 1996 Apple Users' Group, Sydney
Republished from Applecations, a publication of the Apple Users' Group, Sydney, Australia.
Q: Is it possible to connect SCSI drives to an Apple IIgs these days?
A: It has always been possible to connect a SCSI hard drive to the IIgs. The original Apple SCSI card was released at about the same time as the IIgs.
However, it is getting harder to find the SCSI cards - you can still buy a RamFAST from Sequential Systems, but Apple have stopped making their original and High Speed SCSI cards. There are other third-party SCSI cards, but their software support is pretty poor.
The RamFAST is the best option for the range of devices supported and speed. The Apple High-Speed SCSI card (the one I have) is supported by Apple's system software, and is the most "standard" SCSI implementation (except for termination power).
The original Apple SCSI card is much slower than either of the other cards, and has very limited device support.
Given the SCSI card, all you need is an external SCSI hard drive. Nearly all SCSI-1 and SCSI-2 hard drives will work fine with a RamFast or with an Apple High Speed SCSI card.
Q: If so, what are the limitations on partition size, etc?
A: The ProDOS file system is limited to 32 megabytes per partition. ProDOS 8 only works with this file system, so it is stuck with this limit.
GS/OS requires a ProDOS partition for the boot volume, but current versions can also use the Macintosh HFS file system, which supports volume sizes up to 2 gigabytes. There are reports that the IIgs implementation of HFS is rather flakey when dealing with large volumes, but 128 megabytes or thereabouts should be safe. I've had no trouble with the 100-ish MB partition on my hard drive.
The main disadvantage of an HFS partition is that files on it are not accessible from ProDOS 8. HFS is also noticeably slower than ProDOS when writing files - it seems to take forever to update the directory information (or work out what it needs to do), but the actual data transfer is usually much faster than with ProDOS, because the data can usually be written in a contiguous block without having to preprocess the data.
A popular choice seems to be selecting a convenient number of 32 megabyte ProDOS partitions, then splitting the rest of the disk up into one or a few HFS partitions.
I have four ProDOS partitions and one HFS partition on my 240 MB hard drive. I have system software and applications on the first, data files on the second, random stuff (mainly comms) on the third, and PC Transporter and GNO stuff on the fourth. The HFS partition has comms archives and a copy of the data from a developer's CD-ROM.
With the RamFast, all the software needed is built into the ROM on the card.
The Apple cards use device drivers supplied with the IIgs system software. Partitioning and utility functions are handled by programs included with the system software, or by the software supplied with the card (which is very rudimentary) for the IIe.
Q: Is there anyone here who is successfully printing to a DJ500 via an Applesoft BASIC program? I know that simply pointing the program to slot 1 (or whatever slot you happen to have the DJ500 linked to) is not enough. Apparently there are specific printer codes that are needed so that the printer will accept and print straight ASCII text.
A: Setup your DJ500 dip switches like this:
A = U D U D D D D U B = D U D D U D D D
The printer port settings are all standard EXCEPT instead of 9600, it is set to 19200. Now the following program should work:
10 D$ = CHR$(4)
20 PRINT D$"PR#1"
30 PRINT "This is a test."
40 PRINT CHR$(12): REM FORMFEED
50 PRINT D$"PR#0"
60 END
Q: I've always had a bit of trouble with my external speaker hookup is there an explanation? I bought a pair of cheap computer speakers that connect in a single stereo mini-plug, which fits in the headphone port but they hardly play unless I use a mono adapter. Then they hardly play until I jiggle the plug and pull it half out (this is the mono adapter, now) and voila, great volume! The set up is umamplified, and I'm guessing they're 4 ohm speakers. Should I just get in there and replace the jack, or am I missing something?
A: The jack is fine; the problem is the unamplified speakers you're using. The headphone port on the GS is meant for headphones, not speakers. The difference is that headphones have a higher impedance (typically 32 ohms) than regular speakers (typically 8 or 4 ohms) and require less power to get an audible signal. The solution is to use amplified speakers, or to connect a cable from the GS's headphone port to a line-level input on your stereo amplifier.
Additional note #1: You shouldn't need to use the mono adapter, because the jack on the GS is a stereo jack, but with the same signal applied to both the left and right channels. This allows you to connect stereo headphones and hear the audio in both ears.
Additional note #2: I've noticed that the "plug jiggling" you mention works on other speaker-equipped devices I've used over the years. I think this happens because of the way the jack and internal speaker are wired: when nothing is plugged into the jack, the internal speaker produces sound, but when a plug is inserted into the jack, the internal speaker is cut off. If the plug is inserted only part of the way into the jack, it is possible to reach a point where connection has been made to the signal at the jack, but the internal speaker has not yet been disabled. At this point, the audio amplifier is still driving the internal speaker and is quite happy to drive your attached speaker as well. (Note: this is just my personal hypothesis.)
Q: Does any Apple IIgs have stereo output?
Q: No version of the Apple IIgs (of the two existing motherboard revisions) supported stereo output from headphone jack. However, the Ensoniq 5503 DOC chip built-in to every IIgs, does in fact support stereo (Left/Right channel) output. Apple just never "bridged" the signal from the chip to the headphone jack, though luckily they designed the system so that stereo signal could be tapped. The molex connector on the motherboard provides both sound input and output, which is where a stereo card or audio digitizer comes in.
Stereo cards such as the SuperSonic, SonicBlaster, Audio Animator, GStereo, SoundMeister and others do not create stereo, they just tap the existing stereo signal that's essentially built-in to your IIgs. The same applies with sound digitizing. The Ensoniq also has a DAC (Digital to Analog Convertor) and ADC (Analog to Digital Convertor) that allows you to capture and playback real-world sound at 8-bit resolutions. I believe the Audio Animator used it's own ADC to get higher quality digital sampling, but all other cards didn't do much beyond simple I/O (and filtering) for the what was already built-in the IIgs. Had Apple continued support for the GS, they could have easily added stereo output to the headphone jack and an audio-in jack with microphone (a la Mac LC).
Another interesting note: the Ensoniq chip supports up to 8 independent stereo channels, although all existing stereo cards and software only support up to 2 channels. In other words, you could connect eight stereo speakers (ie, two in front, two in middle, two in back, one above and one below) and create some really interesting stereo surround effects! :-) And the bonus is you wouldn't need certain mind alternating substances or an overly active imagination to get 3-D sound! ;-)

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