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SCSI Problems

This month's clutch of software and hardware problems are mainly of the SCSI variety. Martin Walker deactivates a few suspect devices.

This month I have discovered a lot more about possible problems when attempting to install new SCSI devices. The beauty of SCSI is that you can keep adding devices up to a maximum of seven per host adaptor card (which is the eighth device on the chain), or 15 plus host adaptor for Wide SCSI. As far as the SCSI chain is concerned, there should be no difference between internal and external devices, so it ought to be possible to access an internal device from an external controlling device such as a sampler (as long as you turn off any polling from the PC, such as auto insert notification, which would interrupt the sampler during its accesses).

This approach would enable you to install the cheaper internal model Jaz drive inside your PC, but also access it (with a different cartridge) for sampler use, or do what I was trying to do this month — add a TEAC CD516S internal SCSI CD‑ROM drive, for use both by the PC, and by my Akai sampler with sample CDs. Apart from the cost saving, this route leaves one less noisy cooling fan in the studio, since internal models are cooled by the existing PC fan system. The idea is that, since SCSI is a standard, there are no conflicts, and installation is just a matter of setting an appropriate ID number, and connecting the power and data cables. It seemed such a good idea at the time!

Every device must have a unique identity number; during the bootup procedure, each of these numbers is polled by the host adaptor, to find out what's currently connected. Each SCSI ID has a priority: 0 the lowest, and 7 the highest; the host adaptor itself is normally assigned ID7, to make sure it remains in charge. At each end of the chain, the SCSI buss must be terminated, to prevent reflected signals bouncing back down the cable and causing problems.

If you are solely using external devices, then the host adaptor will be terminated, as well as the final device on the external chain. If you only have internal devices (inside the PC), such as a SCSI hard drive and CD‑ROM, then the host adaptor must still be terminated, as well as the final device on the internal chain. If you have both internal and external devices, then the built‑in terminations must be removed from the host adaptor, since this is now somewhere in the middle of the chain, and the two new end devices must both be terminated.

After removing the small resistor termination blocks from my host adaptor card, I attached the new CD‑ROM drive to a convenient spare power cable inside the PC, connected the ribbon data cable between the back of the drive and the socket on the host adaptor card, and then rebooted. The PC got part way through the startup and then crashed, in the same place, every time I rebooted. Going into Safe Mode showed the same bizarre scenario that I reported in last month's PC Notes — the Device Manager showing multiple instances of the same hardware. Last time this happened was after I installed an update to EZ‑SCSI, and although I recovered by re‑installing Windows 95 in the end, this fresh attack suggested a SCSI hardware problem, rather than a software problem.

I subsequently discovered that the CD‑ROM drive worked fine, but only if I left my external SCSI Syquest drive switched off when first booting the PC. Normally when obscure things like this happen with SCSI chains, the advice is to remove devices one by one (by powering them down before rebooting the PC) to identify the culprit, and then move it elsewhere on the chain, or change the length of the SCSI cable connecting it to the rest of the system. In my case, the CD‑ROM drive was fixed at the end of the chain, as the only internal device, so I had to try moving other devices.

Removing my Akai sampler and two‑metre SCSI cable from one end of the chain, and substituting them with a termination, proved fruitful. Now I had both Syquest drive and CD‑ROM recognised by the PC. I reconnected the Akai to the Syquest drive with a one‑metre cable — the chain was now Akai (terminated), one‑metre cable, Syquest, two‑metre cable, PC host adaptor, internal ribbon cable, CD‑ROM (terminated) — and the PC crashed again. Finally, bowing to other people's exhortations to break the rules, I removed the jumper termination from the internal CD‑ROM drive, leaving the SCSI chain completely unterminated internally. Everything worked fine on the next boot, and it was only after this that I discovered that the tiny jumper on the CD‑ROM worked the opposite way round to any other termination I've ever seen — with the jumper in place, there was no termination, and when it was removed, the termination was added. The moral of this tale? Never assume anything where computers are concerned! And if you get peculiar SCSI problems, stick with them — there may yet be a logical explanation.

However, the Akai sampler now gave hard disk read errors with the Syquest, which it hadn't done before. Returning the cables to their original positions — Akai (terminated), two‑metre cable, Syquest, one‑metre cable, PC host adaptor, internal ribbon cable, CD‑ROM (terminated) sorted this problem out. The sad thing is that, after all this rigmarole, the CD‑ROM drive never did work reliably with the Akai. There's no disgrace in this, since it tends to be the Akai that's temperamental, but it does seem that 4x speed CD‑ROM drives are about the fastest that work reliably with Akai samplers. Unless anyone knows better?

Nuts & Bolts

Yet another utility package arrived for review this month — Nuts & Bolts, from Helix Software, distributed in the UK and Europe by Crossatlantic Software. This seems to be a direct competitor to Norton Utilities, but offers (as always) even more comprehensive and far‑reaching components. These are provided in four main areas. The Repair & Recover section includes DiskMinder (disk diagnostics and repairs), Image/Restore (saves critical disk information in case of future crashes), Rescue (creates a single floppy recovery disk if you get hard disk problems), and Discover (a whole host of useful diagnostics for advanced users). Clean & Optimise includes Cleanup Wizard (disposes of unneeded or unused files), DiskTune (a drive defragmenter that's even more comprehensive than that of the Norton suite), Shortcut Wizard (checks all of your shortcuts for missing files), and Registry Wizard. This one intrigued me, since besides the more usual options to backup and restore, clean up unused references, and repair internal references, it also offers a tune‑up of your entire Registry, rebuilding it from the ground up, stripping out unneeded entries, and re‑ordering everything, much as a hard disk optimisation would. Crossing my fingers and taking a deep breath, I tried it, and ended up with a 23% size reduction in both Registry files — and I've yet to find any subsequent problems. Prevent & Protect includes Bomb Shelter (a 'crash catcher'), Winguage (multiple monitors of system resource usage), Virus Scan, and TrashGuard (protects against accidental deletes). The final section, Secure & Manage, includes EZ Setup (a bit like TweakUI), LaunchPad (easy one‑click start to any applications), Stronghold (file encryption and password protection), Shredder (security wiping of sensitive deleted files), and Zip Manager (compression and expansion of archives).

The whole package is most ambitious, and is claimed to run faster and deal with problems at a deeper level than many competing products. This is one of the most comprehensive utility suites I've seen, and it manages quite a bit that others don't, correctly reporting, for instance, all of my hard drive details (see screenshot), as well as providing very useful benchmark tests for checking the performance of components in your system. However, I did manage to crash my PC on several occasions in consistent ways. I reported my findings to Crossatlantic software, who suggested running the same scenario in Safe Mode, which unfortunately changed little. Having said all this, this package is still staying in my machine, because what it does well, it does extremely well. Once these small problems have been ironed out, it will be a product to be reckoned with. Nuts & Bolts costs around £40 inc VAT. Contact Crossatlantic Software on 0171 228 7036.

Tiny Tips

Here's the solution to another SCSI problem that you may come across when attaching computers to samplers and synths with their own internal drives and SCSI controllers (the Kurzweil K2000 series, for instance). If you find that the Device Manager in your PC shows seven hard drives (or CD‑ROMs) when you only have one, the problem is probably caused by another device having the same SCSI ID, 7, as the internal host adaptor card. If this is the case, each time the SCSI buss is interrogated during the bootup procedure, phantom devices will be found at other IDs. Simply change one of the IDs so that all are unique (most PC adaptor cards can be altered easily), and the next time you boot up, all of your ghostly drives should have disappeared.

Finally, two tiny tips for those with yet more SCSI problems. Using the same make of SCSI cable throughout may help solve problems, since its impedance values will remain more constant; although there are mixed thoughts on this, SCSI ribbon cable is said to sometimes perform better, since each core of the cable will have an earth wire running next to it (shielded cable often only has a single earth surrounding all of the cores). Having said this, finding external ribbon SCSI cables to try may prove more difficult.

Problem Corner

Those of you who read my 'Bottleneck Blues' feature in the August issue already know that certain components of a PC can stop you achieving maximum performance when you're HD recording, even though they work fine in most other applications. Now something else is conspiring to cause problems — the drivers used by some graphics cards. The problem (as always) is anything that tries to be clever by doing something different to attempt to save time overall, resulting in a hiccup in the audio, which would be far happier just plodding along at its own pace. The writers of some PCI graphics card drivers have hit on the idea that they can get better instantaneous performance by locking up the PCI buss until their screen updates have been completed. Of course, this makes the drivers faster, but if you happen to be reading or writing sample data, any lockup longer than 1/88200 of a second (1 byte of a complete 16‑bit word running at 44.1kHz) will result in an audible glitch.

You can test your system by playing a WAV file from any application using a small window (not maximised). Start playback, and then repeatedly grab the title bar of the application, drag the window and drop it somewhere else on screen. If you get glitches and pops, or the left and right channels get swapped, you have a graphics driver with a problem. Apparently, many manufacturers, including Matrox and Tseng, have been made aware of the problem caused for musicians, and there are fixes available. Many thanks to Greg Hanssen of Zefiro Acoustics for helping to publicise this problem. You can find out more on their web site (