Coping With Crashes In Windows '95

AARRGGH! Just as you were about to save, your computer crashes, destroying the only record of your latest musical opus. What should be your next step? Before you douse your PC in aviation fuel and set it ablaze, calm down, and hearken unto the soothing advice of Crashmeister JANET HARNIMAN COOK...

How do you feel when your sequencing session is in full swing and the PC takes a nosedive? Shocked? Disappointed? Angry? Or do you, like me, experience all three? Work may be lost, and time is certainly wasted. But once you've overcome the temptation to open the window and pitch the PC into the street, take a deep breath, and reboot. Keep cool, be patient and bear two points in mind. Firstly, when your PC commits this apparent act of treachery and artistic vandalism, it is because it has encountered something so out of order that it has had to shut down. All crashes have a cause — they're usually attributable to badly‑written software, faulty hardware or user error. Secondly, the best form of crash protection is to save your work after every edit, and regularly back up your major files. In this article, we shall examine the common causes of crashes in Windows 95, how to deal with them, and consider the steps that may be taken to prevent them. By the way, I must emphasise that the inclusion of an application in a crash screen does not imply that that software is particularly prone to crashing! It took a ludicrous amount of data to engineer the Cubase overload and the Wavelab screens were part of the same crash.

Fatal & Recoverable Crashes

There are two basic types of crash — fatal and recoverable. The fatal crash 'kills' the system, and all unsaved files are instantly lost. The PC hangs in a cursorless black screen, or may automatically power down and reboot. A common fatal crash type is a General Protection Fault (GPF), which occurs when an application attempts to access or allocate resources to memory areas to which it should not have access. It is as if the application has forgotten where it should place its data, and dumps it in the wrong place. This could be the result of corruption in the application files on disk, or a maybe a glitch in the software itself caused by poor programming. Normally, GPF crashes are fatal, unsaved data is lost and the application terminates. However, if you have installed GPF recovery utilities, such as the WINProbe 95 CrashShield or Norton CrashGuard, you are given the opportunity to save any unsaved work before closing the application. Needless to say, this can be a life‑saver.

In a recoverable crash, your application displays an error message dialogue box to inform you that a non‑fatal error has occurred. You will be given the option of terminating the program or continuing to run the application. If you quit you will lose unsaved data, so the advisable course is to attempt to continue, then save your work and reboot. Should you choose to ignore the error message and continue to run the application, then you accept the risk of creating corrupt work files. These may simply fail to load, or may even crash the application. Other minor crashes may cause your applications to halt the current task, but do no actual damage. For example, if you overtax your PC resources whilst running Cubase, you will be presented with a dialogue box stating that your system is too slow and playback has been stopped. You are advised to mute audio tracks or choose a less demanding lower sample rate; all very polite! Following a crash, the audio editor Sound Forge will, in a most considerate fashion, give you the option of converting the unerased temporary files back to useable Windows wavefiles (.WAV).

Strictly Illegal

Sometimes, when problems occur, Windows 95 will intervene. A dialogue box appears explaining that an illegal operation has been performed — the PC's way of telling you that something untoward has happened. The details box provides further information as to the cause of the crash. In our example, WaveLab is having difficulties with the soundcard, and the information presented refers to a glitch caused by the Multisound drivers.

A more severe crash is when your application freezes or locks. Although the application workspace continues to be displayed, pointer control is lost, and your MIDI output may resort to playing the Chord From Hell. To free the system, resort to the keyboard reset (Control + Alt + Delete). A pop‑up dialogue box should appear listing active applications. You will then be given the choice of waiting, in case the application is simply busy, or of exiting and returning to Windows 95. If you are unlucky, you will get the dreaded 'Blue Bomber' screen, which starkly informs you that your application has become unstable. The choices are to again return to Windows 95, or perform a keyboard reboot. Either way, your current work is lost. At worst, Windows 95 will crash. If the screen hangs in black, then power down the computer. Wait a minute, then switch back on. This gives the computer time to chill out electrically.

Hardware Malfunction

Physical breakdown is rare, and most faulty components show up during initial installation. The PC boot routines will usually pick up failed devices. For example, if the video card is down, the monitor will not produce a text display. Drive or RAM failure is reported by the BIOS. If installed devices fail — such as soundcards, MIDI interfaces, network cards and SCSI cards — a Windows 95 'Non Detection of Hardware' error message will report the fact. If the fault is intermittent, the device may work properly for a while, then fail and revive seemingly at random. Consequently, tracking down intermittent faults can be tricky! The only evidence of the breakdown may be system instability (which will show up as repeated crashes) and the faulty device will cause other system components to misbehave, which may mask the underlying cause. For instance, a faulty video card may cause MIDI applications to underperform and crash. There may be related clues that surface when you run other applications, such as screen glitches in your word processor. The best way to test for intermittent faults is to replace a suspect component, and if the fault clears up, then your suspicions are confirmed.

Serious hardware crashes are fortunately relatively rare. For real scary 'nothing‑gets‑out‑of‑here‑alive' stuff, how about the rogue power supply that, as it self‑destructs, not only bombs the software but also sends high‑voltage spikes that destroy the motherboard, melt the processor and vaporise the RAM? In fact, probably the worst hardware fault you may experience is a hard disk crash. Drives wear out, and hard disk audio recording in particular takes a heavy toll. Sectors of the drive become permanently unuseable, and the internal format data used to configure storage areas may be corrupted. The drive will become useable only after reformatting, and this erases all previously‑stored information. Data on dead drives can be recovered, but it is a specialist operation, and can be expensive. Prevention is better than cure, and the answer is to regularly back up important files to another drive, to DAT or to CD‑R.

Power Supplies

According to some estimates, over 60% of PC breakdowns are caused by electrical failure. Computers need a constant, smooth, regulated AC flow of mains electricity. However, the quality of mains electricity varies widely depending on where you live, and even on what time of day it is. A blackout is when the power is cut altogether; the less commonly‑known 'brownout' is when voltage level drops. A surge is a sudden gain in current amplitude, and a spike is a sudden rise in voltage. Another common problem, line noise, originates in RF and electromagnetic interference; an example of this is when you put a portable radio near your computer, and it picks up a horrid buzz. In a similar way, the power supply to your PC can be affected by the electrical proximity of photocopiers, microwaves, fridges or air conditioners, as it is typically a basic unit with a low tolerance for such electrical problems. For modest PC setups, £25‑30 will buy a filtered 4‑way output block (plugboard) to protect against line noise, surges and spikes.

Power cuts of less than a millisecond can crash a PC, unless you have an uninterruptable power supply (UPS). When the mains supply falters, an off‑line UPS electronically switches on a battery which gives you five or six vital minutes of power to complete simple tasks, save and quit. Off‑line UPS protection for desktop computers starts at about £100. Occasionally, however, the fraction of a second needed for the off‑line UPS to switch in is sufficient time for the computer to go down. The fail‑safe solution is an on‑line UPS which permanently powers the PC. Prices start around £250.

Slow Hardware, RAM & Drives

System instability can be caused by hardware which is functioning correctly but cannot attain the performance level required by the application. This is most commonly down to lack of RAM, sluggish data transfer rates from hard disk, or a slow processor chip. The new generation of PC applications are extremely demanding. You need a very powerful PC to realise the full potential of 'MIDI + Audio' applications like Logic Audio, Cubase Audio or SAW Plus. A very good way of avoiding crashes is to be realistic about the capabilities of your system, and run within them.

When RAM gets low, performance suffers: the system slows down and exhibits an increased tendency to crash. Closing down applications not in use conserves memory, but bear in mind that Windows 95 needs at least 16Mb of RAM just to run most basic applications. For simple 'MIDI + Audio' multitrack and editing applications 20Mb is better; in fact, the golden rule is that you can never have too much RAM.

Older hard drives may be too slow to achieve the sustained data transfer rates required by hard disk recorders. The application will be subject to playback and record interruptions, and may even shut down. The only solution is to replace the drive with a faster model — you can always use the old drive for less demanding tasks, such as archiving. Drives subject to thermal recalibration are generally unsuitable for use in hard disk recording and CD‑R transfer, as during thermal recalibration the hard drive suspends its data flow. Though the audio data is usually buffered, thermal recalibration can still cause interruptions in recording and/or playback (especially if multiple tracks are in use), and may well induce a crash.

Swap Files, Fragmentation & Corruption

Windows 95 requires up to 50Mb of hard disk for its swap file — the place where temporary files are stored. Less than 50Mb of free disk space will increase the chances of crashes. Applications also grab disk space for temporary file buffers, and after a crash they may be left uncleared on the hard disk. Quarterdeck CleanSweep (£46) is invaluable for removing files that applications scatter around Windows during installation, and is also a must if you copy demos, shareware and PD programs from computer magazines' free cover disks.

In everyday use, files on the PC's hard drive can become fragmented. Rather than being written sequentially, the file is scattered in different locations across the drive, so that to read the file, the disk heads must chase around the drive surface collating the file segments. This slows the drive down considerably, and will cause data transfer rates to drop unacceptably. To remedy this, use the Defrag utility in Windows 95. ScanDisk (also found under Windows 95) is used to check the surface of your hard drive and correct simple errors. It is advisable to run ScanDisk and Defrag after each session to ensure optimum disk performance.

Never power down your PC without first closing Windows. Doing so will cause a crash that could damage application or operating system files. Fatal damage of this type necessitates the removal and reinstallation of the corrupted application. If system files are damaged, you may have to reinstall Windows 95. Unless you have a system backup disk, you will lose your applications' own system files (see the WINProbe 95 box elsewhere in this article), which will mean reinstalling your cards and applications. Please note that the Windows 95 startup disk simply enables the C:\ prompt from which you can reinstall Windows 95. It does not restore customisation preference files such as desktop and taskbar configurations.

File corruption can also occur through poor storage of magnetic media, like floppy disks and DAT. It is best to keep these in a dry, dust‑free environment at an even temperature, and away from electrical cables and RF sources like monitors or televisions.

Viruses & Diagnostics

Data corruption may also be the result of your system being infected by a computer virus. A virus is a program that spreads by attaching itself to a host program or to the computer's boot record (startup area). When the host is run, the virus activates and copies itself to other programs. A common source of infection is pirate software, and the consequences of virus infection vary from the silly and merely irritating (eg. daft messages or graphics flitting unbidden across your screen) to the appalling and catastrophic (complete system crash and self‑wiping hard disk). About 8000 different viruses have been identified in all, and protection is available through utilities such as Norton AntiVirus v2. A shareware alternative for personal use only is F‑Prot (see separate box for details).

Finally, it's worth mentioning that Windows 95 includes its own diagnostics routines — you can examine your system configuration in the Device Manager under System Properties. Double‑click on the computer icon to display Computer Properties and view system resource settings (see Figure 6). If you have devices that do not have specific Windows 95 drivers, they will not appear in the IRQ list. More information on resource settings can be found in Martin Walker's article on installing soundcards, which starts on page 164 this month. Lastly, don't forget that Windows 95 Help includes a Troubleshooter wizard to help you solve hardware problems.

Special thanks to: Trevor Learoyd of Northern Synthesizer Service Centre, Bradford (UPS), Godfrey Small of AMS (Windows 95) and Ben Robinson (hardware). Screen reconstructions by Michael Shackleton.