@Ivan Headache
Length of cable supported depends on the SCSI variant being used.
I used Fast-Wide differential SCSI-2 cables that long and yes, they were in spec. and yes, they worked. LVM SCSI-3 allows even longer cables, I believe.
I seem to remember that SCSI-1 allowed a maximum length of 3 metres from terminator-to-terminator, but on many early midrange systems, the external SCSI port was on the same bus as the internal devices, and once you measured the internal cables that ran to all the drive bays, you often had less than 1 metre available for external devices.
The biggest problem was that all the different SCSI varients used different connectors and terminators, and even when you used the same variant, manufacturers often had their own (often proprierty) connectors (IBM, hang your head in shame!)
I hope that some of the smaller Currys stores survive, although this is unlikely, as they are about the only electrical retailer left on the high street (I know there are the Euronics consortium of retailers, but somehow, they are just not the same). Sometimes, you just have to pop out and buy a toaster/hoover bag/unusual battery in an emergency, and if I have to trek 2x25+ miles to the nearest large town, the only ones who will benefit is HM treasury due to the fuel duty. I know I won't.
I'm with most of you on PC World, however. I have often had to bite my tongue if I am ever in one of the stores listening to advice being given to customers. I once had an open row with the supposed network expert about the benefits of operating a proper firewall on a dedicated PC vs. the builtin inflexible app that is in most routers. Eventually, I had to play the "I'm an IT and network Consultant, and I know what I'm talking about" card just to shut him up.
Tux, because he makes UNIX-like OSs available to all.