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This issue of TidBITS brings an encore to our popular issue #104, which focussed on System 7. This time we have a bunch more System 7 frequently asked questions and answers, along with an editorial on the virtues of the now-obsolete Quadra 700, a report on a nasty and long-standing bug in the Hierarchical Filing System, neat tricks with internal CD-ROM drives, and a passel of MailBITS, including one especially for PowerBook 100 and Duo owners.


Copyright 1993 TidBITS Electronic Publishing. All rights reserved.
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We don't know how many of you have been with us since TidBITS#001, but those who have might realize that this issue marks the beginning of the fourth year of TidBITS. We would like to thank you all for making TidBITS a success. Over 50,000 people in 40 countries read TidBITS each week, and it's all happened by word of net. The best way you can help us keep TidBITS growing is to tell a friend or two about TidBITS. It's free, it's easy, and you can get more information by sending email to: <>. Thanks again for an enjoyable three years, and here's hoping we can reach TidBITS#1000 and mess up my three-digit numbering scheme.

WorldScript info is available from Apple at 800/776-2333, so if you have questions about what script modules are available or how to get them, call that number and choose either 4 or 5 from the voicemail system. For the moment, only the Japanese language module (released last week) is available.

ThoughtPattern Discontinued -- Stephen Zagerman of Bananafish Software announced that the company has suspended all marketing and technical support for ThoughtPattern and is searching for a U.S. publisher. ThoughtPattern is an excellent free-form database that I use extensively to store bits of text from the net. We wish them luck in finding a new publisher.

Bananafish Software -- 415/929-8135 --

TeleFinder 3.0 -- Spider Island Software, makers of the graphical BBS software TeleFinder, announced version 3.0 of the TeleFinder Group Edition Host software, which can be fully controlled via Apple events and Frontier or AppleScript. TeleFinder now uses a multi-server architecture that allows multiple nodes of the same BBS to run on separate, networked Macs, increasing the number of phone lines the BBS can support. An unlimited user package of TeleFinder retails for $425.

Spider Island Software -- 714/66-9260 -- 714/730-5785 (BBS) --

Sleeping Floppies -- Rich Wolfson <>, author of The PowerBook Companion, passes on this helpful PowerBook hint. Apple tells you to shut down the PowerBook 100 before attaching the external floppy drive. The reason for this is not because of electrical danger, but because even though the driver for the floppy drive loads from ROM, the PowerBook 100 sets a bit at startup that indicates whether or not a floppy drive is attached. If you boot without the floppy drive attached, that bit thinks there is no floppy drive, and attaching the floppy drive after the fact won't work. So, follow this procedure. Shut down the PowerBook, attach the floppy drive, boot the PowerBook again, and when it wakes up, put it back to sleep. You can now safely remove the floppy drive, and when you want to use the floppy drive again, assuming you haven't rebooted, you can put the PowerBook to sleep and attach the floppy again. The Duos are even neater; you can attach the floppy at any time to a sleeping Duo because it has the floppy driver in ROM and also includes special docking features that allow you to attach a floppy drive (via the floppy adapter or MiniDock) when the Duo is asleep. Never attach an external floppy to any PowerBook while it is awake!

CD Funkiness

The internal AppleCD 300 may not have a headphone jack or volume control, but it's not entirely featureless. If you unplug the microphone you can record 10 seconds of sound from an audio CD in the Sound Control panel. The switching is automatic, but keep in mind that the files will be huge. When you do this, the Mac mixes the two stereo channels of CD audio to mono and converts them to 8-bit sound, which is similar to what happens with the Quadra's "stereo" input jacks.

In addition, you can boot from the internal CD-ROM, which should significantly ease installing new Systems on those machines. In fact, Apple provides the boot CD instead of a set of System disks. Apparently Apple set this CD up with At Ease to make it even easier to use. The CD contains disk images of the System disks, so users can also make a set of backup disks, just in case. Even though booting from CD will ease the process for users, technical support people should be aware of this difference between normal Macs and Macs with internal CD-ROM players.

Information from:
Craig O'Donnell --
Eric Apgar --

HFS Infestation

I don't know if there is a Pulitzer Prize in computer journalism, but if there were I'd nominate Ric Ford of MacWEEK for this year. Fighting with problems on his Macs, Ric tracked down a subtle and confusing bug that has lurked for years within HFS, the Hierarchical Filing System. Others had noticed the bug, but as near as I can tell, until Ric came along, no one figured out what was happening clearly enough and informed Apple at an official-enough level for the bug to be recorded, tracked, and exterminated.

I haven't personally seen the bug, but its symptoms are that when your Mac crashes, it flashes the question mark rather than rebooting if the affected disk is a boot disk. If the affected disk is not a boot disk, the Finder won't think it's a Macintosh disk and will ask you if you want to Eject or Initialize. Needless to say, this is quite noticeable, not to mention irritating beyond belief.

Here's what's happening. When the Mac starts up, it sets a "dirty" flag in the volume information block of each volume. If you shutdown gracefully, the Mac clears that flag and all works fine. If you crash, the Mac sees the dirty flag on the subsequent boot, and checks the disk's catalog and extents files for damage (it usually finds not damage). Under specific circumstances, the Mac blows that check and thinks the disk is indeed damaged, when in fact all that has happened is that the Mac made an incorrect calculation.

The only fix is to boot with an emergency floppy from Central Point's MacTools, Norton Utilities, or Fifth Generation's Public Utilities and then have the disk recovery program remount the disk, clearing that improperly set flag. Note that these programs will not report any problems in the process because they don't know about the bug; they just know how to clear that dirty flag.

I could describe the specific circumstances necessary to release the bug, but there's no point. Instead, let me point you to a free program that Central Point Software's Dave Camp created on Ric's suggestion. Called Disk Bug Checker, the program can tell you how likely it is that a hard drive will suffer from the bug. Disk Bug Checker, which is available on most online services, including sumex as </util/disk-bug-checker-11.hqx>, checks the size of your catalog and extents files along with your partition's fragmentation level and then tells how susceptible that disk is to the bug. Small partitions are seldom, if ever, affected (which may account for the life-span of this particular bug), and the Disk Bug Checker claimed I wouldn't be susceptible until I had 34,817 fragments. That's pretty unlikely.

The best way to avoid the bug in the future if you're experiencing it is to back up your disk (carefully!) and use the Finder's Erase Disk command (from the Special menu) on that disk, restoring your files when you're done. The Finder will rebuild the catalog and extents files, and in the process may change them slightly from your original formatting program. That may eliminate the problem in some cases, especially for volumes around 85 MB to 95 MB, when the allocation block size is 1.5K. If using Erase Disk doesn't help, reformat your hard disk with a different formatting program or with a slightly different partition size, say plus or minus 100K. That will change the size of the catalog and extents files, which will in turn change your susceptibility to the bug. Apple knows about the bug now, so we can hope that they will fix it for good in the future.

Information from:
Ric Ford, MacWEEK --

Related articles:
MacWEEK -- 15-Feb-92, Vol. 7, #7, pg. 74
MacWEEK -- 08-Mar-92, Vol. 7, #10, pg. 58

Apple's 16-bit Solution

by Glenn Fleishman --

I was saddened to read of the Quadra 700's demise. Once again, Apple has cancelled a model which, despite clear advantages, doesn't fit into their price and product line structure. In the process, Apple complicated the issue of cheaply achieving 24-bit color.

When Apple introduced the Quadra 700 and 900 as the first 68040-based Macintoshes, there was much consternation about price, features, upgrades, and compatibility. The 700 and 900 feature much the same technology, with Ethernet, room for 2 MB of video RAM (VRAM), a 25 MHz 68040 with built-in math coprocessor, and improved access to internal components. Apple quickly replaced the 900 with the 950 (a 33 MHz 68040), making the distinction between models more apparent. With some price cuts and the passage of time, most pricing and compatibility issues disappeared.

Apple's introduction of the IIvx last fall, followed recently by the Centris 610 and 650 (16 MHz and 25 MHz 68040-based machines) tarnished the Quadra 700's sheen. The new Quadra 800, which has a similar price and footprint to the 700, but at 950 speeds, also deadened the impact of cutting the 700.

However, everyone has ignored the fact that the Quadra 700 has a feature not shared by the Quadra 800 or the two Centris models: room for 2 MB of VRAM. Although this seems minor, I believe it to be a crucial underestimation by Apple of the necessity for 24-bit color in the near future. This is primarily true for users of Kodak's Photo CD and color flatbed and film scanners, with lesser importance for users of multimedia and CD-ROM-based video. The Quadra 800 and Centris models, as well as the IIvx, LC, LC II, LC III, and Duo Dock for the PowerBook Duos all max out at only 1 MB of internal VRAM. This amount of VRAM provides 32,768 colors, or 16-bit video. Only the Quadra 950 can still do 24-bit video without an additional video card.

Apple's rationale is two-fold. First, 16-bit video is more than adequate for video replay and most multimedia. Although full-screen, full-motion, 24-bit-per-pixel video capture is possible with such devices as SuperMac's Digital Film board, for the sake of compression and sanity, most video is sampled down to 16 bits, or initially digitized at that bit depth. No more than 16 bits is necessary for representing the dynamic range (or numbers of discrete colors) that occur in a standard video signal. Therefore, you achieve a great savings in storage and an increase in digitizing and playback speed.

Second, Apple believes that few non-experts can distinguish between 16- and 24-bit video (see May-93 MacUser article on large monitors for a taste test they performed). Kodak Photo CD actually uses a 16-bit colorspace (the PhotoYCC colorspace), which is compressed from and decompressed into the conventional 24-bit RGB colorspace.

I maintain that Apple's rationale, although valid in general today, is not a significant enough reason to limit users to 1 MB VRAM, and may change in the near future.

On the first point, although today's standard is NTSC in the U.S. and PAL and SECAM abroad, none of which allow for terrific dynamic range, future standards will allow for substantially crisper displays and broader ranges and distinctions of color. Coupled with this is the rapidly decreasing cost of storage and rapidly increasing speed of retrieval, currently major limitations in video storage.

On the second point, I feel that you don't have to be an expert to appreciate 24-bit video. I have spent the last 20 months working mostly on systems with 24-bit video, and the distinction that I see between those systems and others running 16-bit video is substantial enough for anyone making a cursory comparison to notice. People doing serious illustration using either a PostScript language drawing program like Adobe Illustrator or a bitmap-oriented program like Fractal Design Painter, or doing any sort of photographic manipulation, correction, or compositing in Adobe Photoshop, must have 24-bit video. Although you may see smooth blends and crisp results on screen in 16-bit color, you will have no guarantee of the actual output colors or blends. The new calibration products for the truly serious that are about to come on the market (Kodak's ColorSense system, and products by Agfa, EFI, and others) essentially require 24-bit color.

Apple ostensibly is increasing the market potential of their products by eliminating some circuitry and a few SIMM mounts. I can't imagine this saves more than $15 per machine - probably less since the parts exist in other Macs. Engineering costs are negligible because Apple already designed the Quadra 700, 900, and 950. By the time you go through mark-ups, these missing SIMM mounts and circuitry might translate to no more than $50 on the price sticker.

For the user, however, 24-bit color is more expensive. The internal circuitry in the Quadra 700, 900, and 950 is estimated at approximately 75 percent of the speed of the Apple 8*24GC video display & QuickDraw accelerator card (which displays 24-bit color only on 13" monitors; it drops to 16-bit color on 16" monitors). On the other hand, using onboard video equipped with enough VRAM slots, with the addition of six 256K VRAM SIMMs at a street price of $150 total, the user gains 24-bit on a 13" or 16" monitor (including the capability to use third party monitors), avoids using a NuBus slot, and achieves speeds comparable to a $450 to $600 video card from SuperMac, Radius, or RasterOps. (The Quadra 900 and 950 require only an additional four SIMMs or $100, as they comes with 1 MB of VRAM installed.)

Although video cards from third parties often include extra features like automatic dimming, multiple video modes or pixel pitches, and, with the E-Machines 16" video card, even a 10BASE-T Ethernet port, many sophisticated users never use these features (humbly, I include myself in that group).

To give you the same capacity as a Quadra 700 (two slots and 24-bit video on a 16" video), the Quadra 800 would cost an additional $450 to $600 and would lose a slot. The net difference after subtracting the VRAM cost is $300 to $450 (or 10+% of the cost of the machine extra) for what might have added $50 to the machine's cost.

In an effort to reduce cost, I believe Apple made it harder for many individuals to achieve 24-bit-hood. With the increasingly lower cost of the entire Apple product line in conjunction with lower prices for scanners and the advantages of Photo CD, it becomes harder for users to achieve 24-bit color without exceeding their budgets. The elimination of the Quadra 700 provides an easy way for Apple to slip the Centris computers in the middle of the product line since the Centris 650 and the Quadra 700 are virtually identical in performance. Ultimately, users suffer by their lack of inexpensive expansion. The beauty of Apple's newer machines, such as the PowerBook Duo and Duo Dock combination, is that you can have expandability without paying for it until you need it. Now you'll have to pay more.

The good news is that Apple is clearing out Quadra 700s at prices 50 percent or more below what they were six months ago. The Quadra 700 in the 4/0 configuration is available for $2,000 street price versus $3,800 on 01-Sep-92. A Quadra 700 in the 4/200 configuration is $2,600 street price versus the Centris 650 8/230 for $3,100. Remember the above calculations show that if you need 24-bit video, the 700 4/200 would be $2,750 versus at least $3,550 for the equivalent Centris 650 with a 24-bit video card.

System 7 FAQ

System 7 has been out for several years now, and although some people have yet to switch to it (mostly for incorrect reasons or because it's too much trouble), System 7 is probably the most common System version in use. Apple released System 7.1 last fall, but the modules that make 7.1 a compelling upgrade have only begun to appear. In the meantime, here are some frequently asked questions (and answers) about Apple and System 7 that we did not cover way back in TidBITS#104/System 7. If you use System 7 and have questions beyond these, please check that issue because it answers a ton of common questions.

Errors and Solutions

General Questions


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