 The magazine of the Melbourne PC User Group Hard Disk Failures Made Good or Spinrite is here Ray Watson |
Many years ago when I was a fresh faced computer salesman in a small country town (Hobart), hard disks were something only Government Departments could afford. We were under strict instructions not to sell any hard disks without a warranty agreement, because repairs could only be done in the US, and cost more than the unit. Imagine - five megabyte hard disks cost around $5000.
Most of the hard disks that were sold in those days came back within 6 months, unless the customer had installed a power filter and only used it every second day.
Nowadays, if you haven't got a hard disk, you haven't got a computer. There is no sense in spending $150 on a second floppy disk drive when a 20 Megabyte hard Disk costs around $600, in my humble opinion. [Ed: More like $450.]
Reliability has improved markedly. Sure, the occasional bad batch gets out from time to time, but most people can expect several years of trouble free usage.
However, your hard disk will give up the ghost one day. It will be the day after you forget to back up that crucial set of files, naturally. But why will it die? After all, there is no servicing required like your average car! There are two types of hard disk problem - physical failure, and data loss.
Physical failure results from dropping computers out of windows, sliding them off desks and cheap Korean components. Not much you can do about that! As for data loss, data is only magnetic impulses on the surface of a hard disk. And ridiculously small bits of magnetism at that! When the magnetic impulse fades, or changes position, trouble starts.
You may remember turning your stereo on and hearing that 'thump' in the speakers. Hard disks get 'thumped' by electric currents from the hard disks amplifiers. These become magnetic impulses in the read/write heads, that can 'soften' up any data that happens to be located under the read/write heads at the time. Also, the initial start up results in the read/write heads being dragged across the physical surface of the platter. This rips a few molecules off the surface of the platter, and jerks the heads sideways. A bit like a 'wheelie' in a car.
Many of the programs on the hard disk that have read errors on loading are the most frequently used ones, because that's where the heads are usually left on power down.
So - the moral is, hard disks can be left turned on, or 'parked' before power down. 'Parking' is the process of moving the heads to an unimportant area of the hard disk. Many new hard disks have an automatic 'parking' feature which is activated after so many seconds of non usage (about thirty seconds on some portables). There are also several programs that park your heads, and reduce the problem of start up damage
Drive Alignment Drift is another cause of problems. Mechanical devices are subject to wear and tear, heat and cold, loosening tolerances etc.
The small changes in the read/write heads wouldn't matter usually, as data still gets written in the same place as it will be read later. However, there is some data that hardly ever gets re-written, and that is the Sector ID Headers.
These bits of data are the identification information that shows the heads where each sector starts and ends. This information is placed on you hard disk during the last low level format. If the read/write heads 'drift' to one side of the data track, the sector ID data becomes misaligned from the data, and unreadable.
This results in the data following the header being ignored when the computer cannot identify the correct sector. The tragedy is, the data may still be readable. It's like missing a party because you couldn't see the street sign. Ever seen the message 'Sector Not Found'? That's a failure to identify a sector header.
The other problem that can occur with the data tracks being written in a slightly different position, is that manufacturing defects that were not discovered in the initial testing and formatting, start to appear.
Your data gets written over physical flaws in the surface of the hard disk, with catastrophic results. 'Soft' Sectors, are the bane of computer users. They are areas of intermittent reliability that will hold data one, day, and not the next.
Temperature changes, impurities in the magnetic surface, vibration, power fluctuations etc. play a part in creating and maintaining these nightmares. The standard low level format may get rid of them, but often doesn't. Computer dealers go grey over these types of problems.
Many hard disks operate reliably even though they have these operational problems because of inbuilt error correction schemes. Unseen by the operator, these schemes cover up hard disk errors. The hard disk may need several tries to read data without the operator knowing it. Most modern hard disks can accept up to eleven contiguous bits of scrambled information before reporting a hard error. However, the operator isn't told of impending disaster, and when bad bit number twelve occurs - data is unrecoverable.
A lot of work has gone into curing and avoiding these problems. After much hair tearing and fruitless low level formats, I came across a program called Disk Technician, which did a much more thorough job of testing than the ordinary low level format.
As a result, 'soft' sectors were detected and locked out, tracks were re-aligned, and peace was restored to disgruntled users.
The only trouble was, the program cost around $200 (1/3 the price of some hard disks), was copy protected to one machine, and wouldn't handle over 20 Mb of disk in the initial version.
Many clients had no choice, so they paid the money to get the system going again. Every single one of them to date has re-formatted their hard disks for one reason or another, and thus stopped their own private version of Disk Technician from working. The answer was to ring Perth or the US, to get a special code to restore their copy. Very boring, and not easy!
Last week, I took delivery of a program called Spinrite, from Gibson Research, which is a U.S. company. I was prompted to order it because of three things:
1) Enthusiastic reviews in magazines
2) Good reports from current users
3) $US65.00 (cheap as most Shareware)
So, a letter, a Visa Card number and voila - one copy for me. Yes, it works! Installation was easy. It has a very comprehensive manual, step by step installation procedures, and a wealth of technical notes about different types of controllers and computers. It is not copy protected, though you do dedicate one copy for each machine.
They have a very reasonable corporate licensing policy, ($25 per machine). There is also a very generous OEM policy. Use it on all your computers, free, if you place a 'Spinrite was here' promotional sticker on the machine.
Consultants can run the program over any client's machine once, and then send $10 to Gibson Research. A very reasonable price for a clear conscience. And if that isn't enough, the program can select and install an optimum interleave pattern on your hard disk, without damaging the data.
I was using an interleave factor of 4 to 1 on the hard disks on my computer. That meant that the hard disk was reading every fourth sector when recovering data.
Spinrite suggested a ratio of 3 to 1, for an increase of 125% throughput. So I put Spinrite to work, without backing up my data. After 7 hours of testing and low level re-formatting, I had 2 ( C and D) defect-free disks and a snappy interleave of 3 to 1.
Some people have RLL controllers. An RLL controller will do clever things to allow you to store much more data on your hard disk. Spinrite will still work on most of these drives.
Spinrite will not work on some 30 Mb RLL Hardcards, Plus Development Hardcards, HP Vectra drives, or with Western Digital 27X RLL controllers. Gibson Research do not support Toshiba laptop drives , but do say that they could triple the Toshiba's performance. They do not support Priam Drives. They do support drives using clever software like Golden Bows VFEATURE DELUXE, OnTracks DMDRVR.SYS, and Speedstor's HARDRIVE.SYS.
Spinrite also provides a very quick head park facility that doesn't require you to re-boot after its use. They suggest you use it always.
Well, like everything in computers, the stuff gets better, cheaper and easier to use. I can happily say that Spinrite is the flavour of the month for troubled disk drives, and excellent value.
Reprinted from the March 1989 issue of PC Update, the magazine of Melbourne PC User Group, Australia
