USB hub

I now have a USB scanner, printer, Zip drive, Wacom tablet, MIDI interface, keyboard, and mouse. Which hub should I get to save me connecting and disconnecting them all the time?

Mark Paterson

There’s a wide choice of different USB hubs claimed to be compatible with Macs, any of which could work well for you. With so many peripherals, you’ll either need to buy a couple of four- or five-port hubs, or a single seven-port model. Make sure you get powered hubs, and use them with power supplied. Otherwise, you may find the requirements of all the devices connected to a hub will exceed the power it can deliver. Judging by reports, no USB hub is completely free of problems, although early Belkin models and some Entrega products seem to cause the most complaints. Provided you buy from a reputable supplier, you shouldn’t have difficulties returning a hub which is causing trouble. You may also find it helpful to have a tool to inspect the USB hub and peripherals: Apple’s USB Prober is supplied free with the USB SDK, available from developer sections of Apple’s support sites.

JavaScript password

Is there a Java or similar utility for creating password-protected areas on Web sites?

Paul Stanton

It’s not hard to write JavaScript code to enable a password-protection system. (Full Java is actually a very different thing altogether, and is a much more complex thing to get to grips with.) You may find example code in the vast number of books about JavaScript programming, and on Web sites. However, this type of approach to security isn’t going to be particularly secure, as it’s easy to examine the code and so to hack it, or just to hack through the passwords. The best password-protection systems for Web sites are implemented at the Web server end, using compiled programming languages and professional programmers. Most ISPs should be able to offer these facilities, but they’ll only do so for sites hosted under commercial arrangements. So if you’re serious about having truly robust password protection, it’s going to cost you, at least a bit.

MIDI connection

Can I connect a MIDI keyboard to an old PowerBook 100? What MIDI sequencing software could I use?

Jon Higgins

Although most current MIDI interfaces now connect to USB ports, older models for serial ports are still available from several manufacturers. For example, Midiman’s Macman will plug into the serial port on pretty well any Mac, and there are equivalents from MOTU and Opcode. Make sure you also buy decent MIDI cables, or you could suffer baffling problems trying to get the keyboard to work properly.

Unfortunately, most MIDI sequencing software now requires a Power Mac, although a few products will still run on 68040 models. G-VOX (at www.gvox.com) may still offer a 68K version of MasterTracks Pro, which should run on your PowerBook. If you have trouble getting a copy, it would be worthwhile visiting specialist music shops and looking for second-hand copies of older releases.

For a number of reasons, your PowerBook is unlikely to prove an ideal music platform: it’s very slow, and doesn’t handle precise timing tasks very well. An iMac and USB MIDI interface would be far superior, perhaps retiring the PowerBook 100 to process words alone.

Bomb on startup

At most startups, my 20th Anniversary Mac delivers a bomb alert with a ‘bus error’ and then freezes. It starts up fine if I turn extensions off, though. Reinstalling Mac OS 8.6 fixes this temporarily, but it soon returns. What’s the problem?

Chris Whatmore

This could be any of several dozen problems, including a virus infection, but is most likely to be some form of software or hardware conflict. Check for viruses with a combination of shareware tools such as the discontinued (but still helpful) Disinfectant, WormScanner and others, or a commercial anti-virus product such as Virex.

If this checks out clean and you don’t have a clue as to what’s causing the problem, start by shutting down the computer and disconnecting all non-standard peripheral devices. Start up your Mac using the Mac OS 8.6 CD-ROM, run Drive Setup to update your hard disk drivers, restart, and then run Disk First Aid to repair any problems on your hard disk(s).

If you have third-party disk repair tools, such as Norton Utilities, TechTool Pro, or DiskWarrior, use those to ensure your disk(s) are in tip-top condition. Next, turn your attention to your System Folder and extension conflicts. Strip out all non-Apple extensions, and control panels, and re-install Mac OS 8.6. Test this setup: if the startup bombs have gone, then you know that your problems stem from software conflicts (for example, extensions) or one of the removed peripherals. Slowly add them back until you either identify the component which causes the problems again, or you have restored all that you need. A neat way to diagnose extensions conflicts is to install Conflict Catcher, a replacement for Extensions Manager. If your stripped-down Mac won’t run reliably, suspect a hardware problem, which will need your dealer’s attention.

Locked hard disk

I know this is silly, but I ran LockHD from the Ultimate Mac Survival Kit CD-ROM on my blue-and-white G3, after which it crashed. Now I can only start it up from a Mac OS CD-ROM, or from its single internal disk with the extensions turned off, and can do nothing useful with my computer. How can I get it back?

Nick Brown

Like many utilities, LockHD is great ­ and irreplaceable ­ when needed. But if you run it without thinking, it can really mess up your life. If you run it direct from a CD-ROM without copying it to your hard disk first, then it can pose a very serious problem. LockHD works by toggling a flag on your current startup disk, to switch the disk between being locked and unlocked. What you did was to lock your startup hard disk, which will prevent you from starting up from it again, unless all extensions are turned off (holding down the shift key during startup).

If you had run LockHD when there was a copy on your hard disk, recovering the disk by unlocking it again would have been tricky but no real problem: restart from the hard disk with extensions turned off, and then run LockHD to toggle the locking off again. However, you now can’t do that, as you can only start up from your hard disk with all extensions off, preventing access to LockHD on CD. As you couldn’t then run LockHD again from CD-ROM, you’re stuck.

A utility called Unlock Disk can be found at ftp://www.vortex.uk.com. This will attempt to unlock a disk of your choosing, which may well cure this problem. But you’d probably have to download it and burn it onto a bootable startup CD, or put it on a Mac on the same network, boot from your startup CD, locate the utility on the networked Mac, and run it from there.

If this isn’t possible, you’ll need to dig out your Norton Utilities rescue CD-ROM. In the latter case, start up from the CD-ROM and run Norton Disk Editor+, which allows you to fiddle with dangerous settings on your disks. Open the startup hard disk, and display the volume header information. Edit the Volume Attributes field to read 00000000 (all zeros), save the changes, and your hard disk will no longer be read only. If you can’t do that, you’ll need to take your Mac to a good engineer in an Apple dealership.

Parallel printer

Can I use my Epson 700 printer, with a parallel interface, with an iMac? Do I need an adaptor?

Jon Whitbread

The Epson Stylus Photo 700 inkjet printer has an optional USB interface available, which would make it easy to connect to your iMac. This consists of a special USB-to-parallel adaptor, together with the right printer driver to support it. The do-it-yourself approach, of buying a third-party USB-to-parallel interface, might seem cheaper, but you’re unlikely to get it to work properly unless it comes with specific support, including software drivers, for the printer.

G4 processor

A friend told me that all Power Mac G4s are faulty, and run at 50MHz less than specified, because of a heat sink problem, to prevent overheating. Is this true?

Sanj

This isn’t true, although there’s a grain of truth in what you’ve been told. Processors aren’t normally made to run at a specific speed, but are assigned to a suitable speed when tested during manufacture. Processors which work well when run at the highest clock speeds are given the highest speed gradings, and in this case would be sold as expensive 500MHz components. Those that can’t hack that are tested at progressively lower clock speeds, until their highest reliable speed has been identified. They’re then marked and sold as cheaper, slower components.

The percentage of processors made which can be graded to a given speed is known as the ‘yield’. PowerPC G4 processor yields at 500MHz were poor at first, and insufficient for Motorola to offer commercial quantities to Apple. This resulted in early adopters being offered G4 models with clock speeds 50MHz below those originally intended. Thankfully, this has now eased, as yields of 500MHz components have risen. Finally, G4 processors run quite hot, so Apple can’t yet offer G4 PowerBooks. But in desktop models, heat sinks are coping just fine, and PowerPC processors normally have less cooling problems than equivalent Pentium processors.

Disk partitions

Should I partition the 6Gb and 10Gb hard disks in my blue-and-white G3 and G4 computers?

M Webb

Before Mac OS 8.1, large hard disks were often partitioned to ensure they could be accessed efficiently, and so they didn’t waste too much disk space. This was because the Mac OS’s old hierarchical filing system (HFS) could only divide a hard disk into just over 65,000 storage units of fixed size so, as disk capacities rose, the size of those units became correspondingly large.

Initialising a hard disk with the extended version of HFS (HFS+), under Mac OS 8.1 and later, not only allowed it to waste less space, but also delivered acceptable performance even on very large volumes. As such, from Mac OS 8.1 onwards, partitioning a single large disk into two or more volumes became less worthwhile. The only exception remains when you need a single volume to provide a large block of free disk space. For example, when working with digital video, if you can keep such files on separate volumes, you needn’t worry so much about defragmenting the volume to make free space contiguous.

Having said that, many users still find it more convenient to split large disks (bigger than 4Gb or so) into smaller volumes, by partitioning them. The directory data structures which locate files then remain smaller, and more manageable, making some file operations quicker. You can also install more than one System Folder, to switch between different versions (for example, Mac OS 8.6 and 9) or languages (say, English and Kanji). But above all else, you may find it helps you navigate the contents of the disks more easily. So you don’t need to partition those disks, but you may well find it easier if you split them into volumes of around 2Gb to 4Gb each.

Old Macs on the Internet

My father-in-law has been given a IIvi. Can this be used to access the Internet? What’s the most recent version of the Mac OS that will run on it? Is it worth upgrading?

Marcus Byron

The Mac IIvi was a 68K model sold during 1992 to 1993, with a 16MHz 68030 processor. The most recent recommended version of the Mac OS for it is System 7.5.5, so it can’t run any recent Mac software designed for Power Macs. It has limitations to the maximum amount of RAM which can be installed (68Mb), and severe restrictions on the monitor resolution support, making it of limited value for serious Internet use.

If you do want to use it on the Internet, you’ll find email and Usenet news acceptable, but trying to run a Web browser will quickly become frustrating: many of the more popular Web sites require plug-ins and features only found in the more recent releases of browsers. Finding old 68K versions of email and other applications is also likely to be quite tricky now.

Rather than devote time and money to this old Mac, your father-in-law would do much better to get a new or second-hand iMac, which will provide a much more fulfilling Internet experience.

Linux on G3

I need to run Red Hat Linux on my blue-and-white G3. What’s the best way to do this?

Grey Skipwith

Although Power Macs can now run several native versions of Linux, including MkLinux, Yellow Dog, and LinuxPPC, Red Hat isn’t yet supported. If you really must run Red Hat, the only solution is to buy Connectix VirtualPC, and install Red Hat as its operating system. Recent versions of VirtualPC have made this considerably easier, and you may be able to get a bundled deal with both products. If that combination doesn’t address your needs, you would do best to get a cheap PC specified to run Red Hat right from the box.