PowerBook Tips v.2.51 (4 September 1992) copyright Bernard Khoo (c) 1992 Notes ----- 1. Many of these tips are common to all the PowerBook range. I have noted differences where I know of any. 2. Many of these tips are referred to in the manual. I cannot emphasize how important it is that you read the manual thoroughly and carefully. In my 7 years of Mac ownership I've managed to escape reading many manuals, but not this time! 3. Thanks are due to the following: * John Livesey (livesey@radonc.washington.edu) * Murph Sewall (SEWALL@uconnvm.uconn.edu) * David Tillinghast (David.M.Tillinghast@dartmouth.edu) * Shannon Spires (SVSPIRE@sandia.gov) * Thomas Rothenfluh (rothen@cis.ohio-state.edu) * Alan Hewat (hewat@frill.bitnet) * Norton Chia (norton@au.oz.su.ucc.extro) * Dave Platt (dplatt@ntg.com) 4. A similar document in SUMEX-AIM, /info-mac/report/powerbook-faq.txt, has some additional tips and technical data that you may find interesting. DISCLAIMERS and WARNING: I have not tested all of these tips yet. Whilst I have taken care to make sure that they are correct, I disclaim responsibility for any mishaps/ accidents/disasters that may ensue from the use of these tips. Please be careful when using them. I have no affiliation with any company producing any commercial products mentioned below, except as a user of their product. This document solely expresses my personal opinions. Things to buy/download ---------------------- 1. Buy more RAM. The PBs contain 2MB installed on the motherboard and an expansion slot. Add a 2MB card to get 4MB total, a 4MB card to get 6MB, and a 6MB card to get 8MB. PBs with 4MB come with a 2MB card already installed, so a 4MB -> 8MB upgrade, for example, means that you have to buy a 6MB card and pull out the 2MB card. 4MB will allow you to run System 7 and one or two fair-sized applications. However, you will probably run up against the wall at one time or the other, so it's probably best to grit your teeth and save for an upgrade to 6 or even 8MB. It's important to buy pseudo-static RAM rather than the cheaper dynamic RAM -- dynamic RAM will drain battery power faster. Don't forget to ask for a rebate on the 2MB card, if available -- the 2MB RAM card is just about as saleable as a 256K SIMM, i.e. not very! 2. Download the PB Sleep FKEY (freeware). On SUMEX-AIM this is at /info-mac/fkey/powerbook-sleep-10.hqx. This is an extremely useful and small FKEY which switches off AppleTalk then puts the PB to sleep, bypassing the annoying dialog which pops up when you use the Finder Sleep command with AppleTalk on. 3. Get AutoDoubler/SpaceSaver/SuperDisk. These save you hard drive space by compressing files on the disk and decompressing them on the fly. I have AutoDoubler installed: at most times there is an acceptably small performance hit, files are compressed to about 1/2 size, and I have yet to experience any major problems with the program. However, I have only gained about 16MB of virtual space -- due to the large size of my System Folder, which is kept uncompressed. 4. Download SuperClock! 3.9.1 (freeware). On SUMEX-AIM, this is at /info-mac/cp/superclock-391.hqx. The battery gauge that appears on the menu bar is incredibly useful, more so than the Battery DA. However, the battery icon only indicates half-full on PB170s (and probably on PB140s as well) when your battery is actually almost completely discharged -- this is a property of NiCad batteries, whose voltage declines with discharge in a non-linear fashion. The icon works properly on a PB100, whose lead-acid batteries discharge more predictably. Trivial hint: control-clicking on SuperClock puts the machine to sleep. Unfortunately this does not switch off AppleTalk and brings up the annoying Sleep dialog. You'd probably be well advised to use PB Sleep (see above). 5. Buy a multimodule application. e.g. ClarisWorks, MS Works, BeagleWorks, GreatWorks etc. These are OK for most use on the field, take up little drive space and memory, and can be installed in a RAMdisk (see below). 6. Download InUse 2.0 (freeware). On SUMEX-AIM as /info-mac/cp/in-use-20.hqx. This flashes an icon on the menu bar every time the drive is accessed, and is slightly more practical than listening carefully to the computer to determine whether the hard drive is being used. 7. Download PB Tools 1.2 (freeware). On SUMEX-AIM as /info-mac/util/power-book-tools-12.hqx. This package by Bill Steinberg includes SpinD FKEY, another small FKEY which spins down the hard drive, and SafeSleep, a simple INIT which asks for a password before waking the computer from Sleep. 8. SCSI operation with the HDI-30 SCSI Disk Adaptor cable (PB100). If you have a desktop Mac and a PB100 this cable allows you to operate the PB100 as a SCSI drive from the desktop Mac. This is especially convenient for installing systems and copying files between the two. Unfortunately this works only with the PB100 and not with the other models. For instructions, read the manual. Please note that the SCSI Disk Adaptor cable used here is different from the SCSI System cable used to connect all the PB models to SCSI devices, although they look similar. Getting the most from your hard disk ------------------------------------ 1. Use the space you never knew you had. If you received the computer with System 7 pre-installed, chances are that the drive was formatted using a standard Macintosh volume partition to 40MB. [Trivial fact: according to MacUser this was because the Apple Tape Drive could only take 40MB of data.] There is usually another 1.6MB free space on the drive. To exploit this: a) Backup your hard disk completely. b) Boot up with the Disk Tools floppy (from the System Disks package). c) Fire up HD SC Setup. d) Initialize your hard disk. e) Select Partition. You should see a rectangle representing your hard drive, subdivided into: (from the top) Mac Driver, and a grey area (the free space). f) Select your 40MB hard drive partition and click Remove, then OK to confirm. g) Click in the now-larger grey area. h) Select 'Macintosh Volume' in the dialog that pops up and type in the maximum size of the partition (the dialog will tell you what the maximum size is -- usually 41600). i) Click OK and quit HD SC Setup. j) Restore your hard disk from the backup. 2. Get AutoDoubler etc. (see above) 3. Consider an upgrade to a larger hard disk. There is an official Apple upgrade, although there are also cheaper third-party upgrades (up to 120MB at the time of writing). However, these upgrades may be noisier and consume more power than the 40MB Conner. 4. As always, take a long hard look at the files on your drive. Are all those extensions and control panels really necessary? Removing them will save you drive and memory space, and can only decrease your chances of an INIT conflict. Do you really need all the help files that came with your application? (Claris Help Files are especially large!) Or even the tutorial files? Fonts (outline and _especially_ bitmapped) should be cut down to the minimum -- if you're doing DTP, you've probably got the wrong machine! Alternatively, MasterJuggler and Suitcase II both come with font compression utilities. Rationalise the files stored on your hard disk: include only those files and programs which you will use most often on the road, and archive less-used items on floppies or an external hard disk. You can leave aliases, which only take 1K each, to these files in the appropriate places on the hard disk. Double-clicking these aliases will bring up a prompt for the appropriate floppy to be inserted. A screen saver is unnecessary on a PB. Actually it seems to me that they are generally unnecessary anyway! 8-) It is true that a sort of 'burn-in' effect can occur if the screen is left on for prolonged periods, but you can always put the computer to Sleep. (If you are a victim of this effect it can be reversed by simply switching off the screen for a few hours.) Power issues -- or how to save, save, save ------------ 1. Creating a RAMdisk to use as a startup disk. Requires 8MB to be practicable with System 7. Steps i) to iv) to be done once only, a) to d) when you are preparing to go out. i) Create a 4+MB RAMdisk using the control in the Memory control panel. Restart. The computer will ask you if you want to initialize the RAMdisk -- answer yes. ii) Install a System Folder (SF) on the RAMdisk using the System disks that came with the computer. Install any applications, control panels, extensions, fonts and ancillary files on the RAMdisk. Compress a copy of the RAMdisk onto your hard drive using Stuffit, DiskDoubler, Compact Pro etc. iii) Set the RAMdisk to be the startup disk and restart. The computer should now run faster and use less power in this configuration. iv) Copy the compressed copy of the RAMdisk to floppies and take this with you in case of emergencies. a) Set up the RAMdisk using the Memory control panel. b) Decompress the compressed archive onto the RAMdisk. To convince the PB that this is actually a viable SF, drag the System from inside the RAMdisk's SF to the open SF icon. c) Using the Startup DIsk control panel, set the RAMdisk to be the startup disk. d) Restart. The PB should boot from the RAMdisk. Note that Shut Down erases the RAMdisk on PB140s and 170s, so use Sleep to switch off the computer when it is not being used. On the PB100 it is possible to create a 1MB RAMdisk containing a very minimal System 6.0.8, ClarisWorks (only the application is needed) and some small documents. This means that it is possible to run ClarisWorks on a PB100 off a RAMdisk with only 2MB! Incidentally, the RAMdisk on the PB100 is more robust than the one on the PB140/170: it survives Shut Downs. 2. Hard drive discipline. Apple has implemented this by allowing you to set a delay time after which the drive will stop spinning (find this in the Portable control panel). I'm afraid only trial and error will allow you to find a suitable setting to your liking. Also, Bill Steinberg's SpinD FKEY (see above) allows you to stop the hard disk electively. If you require access to the drive, once the drive is still, the PB will do a very good imitation of a system freeze whilst the hard drive spins up. Frequent stopping/starting wastes power and also annoys. It only takes a little foresight and discipline to minimize this: a) Open up any DAs, control panels, or applications which you are likely to need in a work session beforehand. b) If you have any font or style selections to make, try to leave them till the end, just before you save. More often than not, the PB will load a font from the drive when you make a change. Learn to spell as you go, instead of using a disk-intensive spellchecker! c) Try to go for long stretches before saving. In this case, auto-savers may be a waste of power. Of course, you have to balance this with the need to save often to protect against crashes! d) Choose your work applications and DAs carefully. Many of the mainstream packages are very disk-intensive -- the worst culprits being DTP programs. I personally find that ClarisWorks is quite well behaved in this respect. Consider loading MS Word (v4.0) completely into memory. e) Load your work applications into a RAMdisk. This saves having to start up the disk every time the application wants to redraw a window, load a dialog box etc. A good program for this purpose I have seen is AppDisk 1.5 by Mark Adams ($15 shareware). This program uses application memory as a RAMdisk, which gets over the inconvenience of having to restart time and time again to reclaim memory back from the RAMdisk -- the built-in RAMdisk sequesters memory in the System Heap and requires rebooting before its size can be changed. AppDisk does not survive restarts (again, unlike the built-in RAMdisk), but can be set to auto-save its contents onto hard disk. You can create multiple copies of AppDisk: one containing (say) MacWrite II, another containing FileMaker Pro and so on. Launching one of these sets up a RAMdisk containing that application. Find this program on SUMEX-AIM at /info-mac/util/app-disk-15.hqx. f) An alternative to loading applications into a RAMdisk is to set up a large disk cache of about 2MB (the control for this is in the Memory control panel). Launch your set of work applications: this will load them into the cache. Then switch off the hard disk with the Sleep command or the SpinD FKEY. Any disk accesses made by the applications should be obtained from the cache, and the disk should now not be spun up by the PB. [This tip from the documentation to SpinD FKEY.] 3. Backlighting. The backlight consumes a lot of power (some 40% of the power consumption). Most times, 50% or less intensity is fine, and saves some power. Alternatively, find a bright place to work and switch off the backlight. (Not so easy in the midst of a British winter!) Backlight Control, a fine control panel by Ricardo Batista, allows you to set a period of inactivity after which the backlight is switched off. (Apply to me for copies.) 4. Power-saver mode (only in the PB170). The power-saver mode in the Battery DA (accessed by clicking on the toggle switch to the right of the gauge) slows the processor down to 16MHz to save power. This is acceptable for most use, and makes a large difference to power consumption, adding an extra 30 minutes (Apple estimate). 5. Rest mode. This mode cuts the speed of the computer to 1/20 when it detects no activity on the keyboard or trackball for a set period, to save power. Rest mode may interfere with some programs which are processor-dependent. If Rest mode interferes with the operation of your program, open the Portable control panel and option-click the 'Minutes until automatic sleep' text. A dialog box will pop up allowing you to choose between Rest/Don't Rest modes. An alternative is to download the Powerbook OK to Rest and Powerbook Don't Rest utilities (SUMEX-AIM: /info-mac/util/powerbook-rest-norest.hqx). These are small applications written by Insignia Software which set the PB to the appropriate mode. For ease of access, leave aliases to these programs in the Apple Menu Items folder. The effect of Rest mode is most noticeable with the text cursor: after a few seconds of inactivity the cursor will suddenly flash much more slowly. This is a feature, not a bug (as they say) -- some posters to comp.sys.mac have been surprised by this phenomenon! 6. Batteries. The manual advises you to discharge the NiCad batteries in the PB140/170 fully every 90 days, to maximize its life. This procedure involves using the computer until it goes into Sleep mode automatically after the third low-power warning dialog: "No battery reserve power remains. The Macintosh will go to sleep within 10 seconds to preserve the contents of memory. Good Night." There are battery charger/conditioners (sold commercially) which supposedly discharge the battery even more and maximise its life. However, from a recent post to INFO-MAC, the following advice was given: > Date: Fri, 7 Aug 92 13:40:36 PDT > From: dplatt@ntg.com (Dave Platt) > Subject: battery cyclers for PowerBook > > The "memory effect" is almost never observed in NiCd batteries used in > consumer applications. It occurs only when a NiCd battery is repeatedly > discharged to _exactly_ the same level and then recharged, many times in > a row. This can happen in some very specialised applications, but won't > occur in a typical consumer application such as in a PowerBook. The > "virtually random cycling and use" that you are giving your batteries is > exactly the sort of use which ensures that the memory effect won't occur. > > There is an effect in NiCd batteries known as "voltage depression", > which occurs if you overcharge the battery (if you leave it cooking in a > high-rate charger for too long). This effect lowers the output voltage > slightly, and it can make the battery _appear_ to lose capacity (because > its voltage drops to the 1.1-volt threshold sooner than it would > otherwise). Voltage depression can be reversed by completely > discharging each cell in the battery, and then recharging it. > > It's safe to discharge individual NiCd cells (1.2 volts each) all the > way to zero. It is NOT safe to discharge a NiCd battery all the way to > zero - the first cell to be exhausted will be damaged by the continuing > flow of current through it. So... don't try to discharge your PowerBook > battery by hooking it to a flashlight bulb or a resistor. > > The PowerBook has a low-voltage detector, which detects the fact that > the battery voltage has dropped to near-exhaustion (usually 1.1 volts > per cell) and shuts down the machine. It's a bad idea to try to use any > NiCd battery beyond this point -- you risk damage to the battery, and > there's only about 1% of the useable power left anyhow. > > So... the best way to exercise your PowerBook battery (to eliminate the > effects of voltage depression) is to use it until the PowerBook warns > you that low-power shutdown is about to occur... then, sleep the > machine, take out the battery, and recharge it for the recommended > length of time (but not for longer than that). This should bring the > battery back up to full charge, without overcharging it. > > Dave Platt VOICE: (415) 813-8917 > Domain: dplatt@ntg.com UUCP: ...netcomsv!ntg!dplatt > USMAIL: New Technologies Group Inc. 2468 Embarcardero Way, Palo Alto > CA 94303 For the PB100, an IMPORTANT NOTE: the PB100's lead-acid batteries are easily DAMAGED by total discharge, as can happen if the computer is left in storage for more than about two weeks without disconnecting the battery using the storage switch on the back (p.225, manual). The manual also advises not using the PB100 until the third low-power warning dialog -- occasional use to this point is OK, but repeated discharge may damage the battery. There is _no_need_ to discharge them before recharging. For tech-heads -- Volt (/info-mac/util/pb-battery-voltage.hqx at SUMEX-AIM) gives you a reading of the voltage being supplied by your battery. Consider buying a spare or two for trips, in which case a battery charger is also useful for charging two packs at a time -- both of these are Apple accessories. Apple has announced that the terminals of PB140/170 batteries are vulnerable to shorting, a situation that can be dangerous. They supply battery cases for free to protect the terminals. Remember -- once the batteries are dead, send them back to your nearest Apple authorised dealer for recycling. 7. Sleep. If you have the Powerbook Sleep FKEY (see above) there should be no excuse not to send the PB to sleep whenever possible! I am not sure what harm can be done to the PB if it is carried around in Sleep mode (thus saving you from having to wait for the computer to restart), although Apple recommend that you Shut Down before moving the PB about. [It is thought that it may be possible to activate the computer when it's closed -- possible harm may ensue from shock damage to the hard disk, in such a case.]. So far, I haven't damaged my PB by carrying it around in Sleep mode (touch wood!). 8. Setting the desktop pattern to white. [David Tillinghast's findings] Pixels 'on' (i.e. black) on the screen take up power because they have to be refreshed; in an (extremely unscientific) experiment it was found that an all-white screen lengthened battery life by about 12 mins. Take this how you will! 9. Other ways to save power. Don't bother with virtual memory -- it's slow and it gobbles up battery power. If you do have to use it, make sure you're plugged in. Switch off your internal modem, if you have one, whenever possible by quitting all telecommunications applications as soon as you are finished. Switch off AppleTalk whenever possible. (I think this is a relatively minor power drain, though.) If you use an ADB device (e.g. a keypad, mouse or some makes of modem), make sure that they are low-power devices. Other tips ---------- 1. How to connect a SCSI drive to the PB. In the manual, connecting a PB to an external SCSI drive requires an Apple accessory HDI-30 SCSI System cable and an external 'pass-through' terminator: PB --- HDI-30 SCSI --- external --- drive with internal cable terminator terminator ON In practice, it is possible to omit the external terminator; problems are encountered occasionally especially when copying files, causing system hangs from which the PB has to be reset. It seems to be OK for reading files from the external drive. If you need to use a SCSI extension cable you require the following configuration, as Murph Sewall and Thomas Rothenfluh have found out: PB --- HDI-30 SCSI --- external --- extension --- drive with internal cable adaptor terminator cable terminator ON 2. Velcro straps in the Apple briefcase-style bag. Tightening the bindings too snugly can warp the panel on the back of the PB and prevent it from closing properly, so be careful not to tighten too much. 3. Modifying the sensitivity of the PowerBook trackball. The PB trackball at first takes some getting used to. In many cases you will need to set a low sensitivity using the Mouse control panel. An alternative which I use is the Pointing Device control panel (mirrors3/ archive.umich.edu/mac/system.extensions/cdev/pointingdevice.cpt.hqx at wuarchive.wustl.edu) which allows custom modfication of the trackball response. (Be warned, though, that the package comes with minimal instructions, and is also 'mysteryware' -- in other words, nobody is sure whether this is actually commercial, shareware or whatever.) Other trackball manufacturers (e.g. Kensington) include similar control panels with their products. Some users report that the PB100's small trackball is insufficiently heavy and have reported good results by substituting glass marbles (25mm diameter) -- a so-called 'shooter'. Marbles in the PB140/170 trackball's size are apparently manufactured but not sold commercially, although no doubt some marketing wizard will find a way of making PB users pay over the odds for such marbles. 4. Using the PB on a desk. The PB's keyboard lacks function keys and a number keypad. Consider buying an ADB keyboard with these features (e.g. the Apple Extended Keyboard II) and a mouse if you use the PB170 on a desk. Buying these also allows you to place them at ergonomic positions (there should be an advisory booklet on ergonomics in your PB package). Note that the Extended Keyboard is a high-power ADB device, so you will need to be connected to your AC adaptor or the batteries will drain quickly. 5. Problems reading 800K disks? (PB140/170) One possibility is that the backlight may be interfering with the operation of the drive. This design fault should not affect PBs built after Feb 1992. If you encounter problems reading 800K disks, try switching off the backlight. If the problem persists, phone 1-800-SOS-APPL or contact your friendly Apple dealer. (This problem is due to improper shielding of the drive from the backlight.) It is also known that the drives on PBs are less tolerant to cheap media, or to disks formatted in drives which are not quite in alignment. This problem crops up most often when installing commercial software, which usually comes on cheap 800K disks duplicated en masse; for example, I had incredible trouble installing MS Word 5.0 on my machine. One workaround is to copy the troublesome disks on a desktop Mac to brand-name floppies, and to use these to install your software. 6. Travelling with your PB. Some useful items to bring along: - a copy of the Disk Tools disk from the System Disk package. - a file recovery utility installed on a minimal System 7 boot-up floppy. (See /info-mac/report/sys7-emergency-disk.txt on SUMEX-AIM.) - spare blank disks. - spare batteries and the AC adaptor. - plug adaptors for the AC adaptor. The adaptor itself automatically compensates for voltage and frequency differences. - your guarantee card. You may need this to obtain repairs from a foreign Apple dealer. - a carnet. This is a document obtained from your Customs Office which may be required when you return as proof that you brought the computer out of the country in the first place. - and a bag to contain all this stuff, as well as your PB. * consider buying insurance for the PB. * and don't forget to make a backup right before you leave, just in case. Ask for the computer to be hand-examined by the security officer, and have a charged battery inside to show that it really works. Do not walk through a metal detector with the PB or floppies -- besides ringing the bells on the detector, there is a chance that the detector may screw up your disks. The X-ray machine, if there is no alternative, is probably safer in this respect. You may want to phone the airline to find out about their policy on the use of notebook computers on board. A particular problem with the active matrix display on PB170s: X-ray machines have been reported to damage pixels on the display. 7. Getting into your PB. Cracking open the PB140/170 (you don't really need to, do you?) requires the use of two Torx screwdrivers: sizes 8 and 10. Remember to tighten the case properly afterwards -- not doing so puts a strain on the pin holding the back panel closed and will eventually break it! The PB100 is held together by Phillips-type screws under grey screw-caps. Be warned that opening your PB (a) invalidates your warranty, and (b) is dangerous unless you know exactly what you are doing. 8. Connecting/disconnecting devices to the ports. It's probably OK to connect/disconnect serial devices to the Printer and Modem ports whilst the computer is in Sleep. However, with ADB and SCSI devices it's advisable to Shut Down before connecting/disconnecting (these connectors have 5V lines which can zap controller chips). You will also need to Shut Down before plugging in the external drive for the PB100, otherwise the PB100 will not recognize it. 9. Swapping escape and tilde keys. If, like me, you find the new position of the escape key annoying, it's possible to swap the keys so that escape is in its proper place in the upper-left corner. The easy bit is levering the keycaps off and swapping them... however, modifying the System software to reflect this change requires a stout heart and some experience with ResEdit. If you'd like to know how to do this I can send you instructions (they are rather too long for this tipsheet). Just apply to me via e-mail. You can use a similar technique to swap the enter and backslash (\) keys. Unfortunately, there seems to be no way to map the caps-lock key to anything useful (e.g. a control key, in the cognate position in other Apple keyboards). 10. Can the PB100 run System 6? You may not be a reactionary diehard like Guy Kawasaki, but System 6 has a major advantage: its memory consumption, which is approx. 200K against the 1.3MB minimum for System 7. This is probably the cheapest way of making a 2MB PB100 useable. System 6.0.8 works on the PB100 although Apple does not guarantee that it will work 100%. I have System 6.0.8 installed on a 2MB PB100; with a fair collection of INITs (Extension Manager, CE Toolbox 1.6.5, Disk Doubler Init, DiskTop Extras, Suitcase II 1.2.12, Super Boomerang, Now Menus, ATM w/ 96K cache and SuperClock! 3.9.1), I have 1MB left. A bonus is that (as mentioned above) a minimal System 6.0.8 can be installed with ClarisWorks in a 1MB RAMdisk. The installation disks may be obtained from your local Apple dealer, or by FTP from ftp.apple.com in /dts/mac/sys.soft/6.0.8. For the latter you will need, in addition to the usual decompression and de-binhexing tools, DiskCopy 4.2 (on ftp.apple.com as /dts/utils/diskcopy-4-2.hqx) to write the disk image files to suitable disks. One problem is that the backlight brightness dial does not work and is ignored in System 6: brightness can be controlled by the Portable control panel using the Screen Contrast lever, although in a slightly counter-intuitive way (move the lever up to decrease brightness and vice versa). To solve this, download the up-to-date version of the System 6 Portable control panel (1.3) from ftp.apple.com at /dts/mac/sys.soft/video/portable-update-1-3.hqx. This updated control panel also allows you to set up a keyboard shortcut to adjust screen brightness. (The screen contrast dial works as usual.) 11. Keeping common documents up-to-date. If you have a desktop Mac as well and store common documents on both the desktop Mac and the PB which you need to keep up-to-date to the newest versions, two programs exist which automate this process. The other Mac is connected to your PB using AppleTalk and File Sharing, or via SCSI (see above). - Zync is a simple freeware program by Ricardo Batista: on SUMEX-AIM as /info-mac/comm/zync-10a3.hqx. - a similar program called Up-To-Date by Ben Hekster (freeware) does the same job (/info-mac/util/up-to-date.hqx). 12. My PB keeps on clicking at me. There's no need to be alarmed. (Again, this is a feature, not a bug!) After playing a sound the PB's Power Manager will switch off the speaker to save power, producing a click. If it really annoys you, you will have to switch off sound using the volume control in the Sound control panel. Any more? --------- Please send any notes, omissions, or errors to me. More tips are welcomed! Bernard Khoo University of Cambridge Medical School, UK. E-mail: BCEK1@phx.cam.ac.uk or @cus.cam.ac.uk (reverse if in the UK) Snail-mail: c/o Sidney Sussex College, Cambridge CB2 3HU. England.