So. You have cloned your OS and files on to your new, shiny hard disk. You disconnect the old disk, take out the CD, flick the switch on the back of the machine and…
you get an error.
“Disk read error”.
The solution, however, might be more obvious than you think.
When your machine starts up, it uses the BIOS (Basic Input/Output System) to monitor hardware, supply power to disks, and to kick-start the operating system’s bootloader. The BIOS is soldered on to your motherboard, and is a little chip. You might spot it, you might not.
The BIOS does many other things, such as switching the machine into standby, monitoring and regulating the temperature inside the machine, and - perhaps most importantly of all - setting the system clock. (It may sound trivial, but it can be critically important for reasons I won’t go into at this time.)
Whenever you boot up your machine, for a few seconds you may see text on the screen DOS-stylee muttering on about ‘testing RAM 262144K OK’ and ‘detecting IDE drives’, and all sorts of stuff you probably don’t care about. Alternatively, the computer manufacturer’s logo may be displayed, or, on some more recent Intel BIOSes, the Intel logo.
This screen generally only appears for thirty seconds at most, and normally stays up for only five. During that time, you will see a line of text that says something along the lines of “PRESS [key] TO ENTER SETUP”. Normally that key is Delete or F2.
(I should point out now that this post does not apply to Apple Mac computers, and only applies to IBM-compatible PCs, ie the posh, overweight man in the ads.)
“How does all this tie in with replacing your hard disk?” you may ask. I’ll get to that shortly.
When you enter SETUP by pressing the appropriate key, your screen will immediately turn a funny colour, and you’ll be presented with a text-based menu. Whenever you get a new machine, it’s always a good idea to look around the BIOS SETUP utility without making any changes, so you know your way around.
I will point out here the fact that neither myself nor Crashed Pips can take any responsibility for any damage of anything, physical, virtual emotional or otherwise, ensuing directly or indirectly from following this advice, which is given in good faith (but with a health warning attached). I’m using the disclaimer seriously here - touching anything in the BIOS which you don’t understand can (and probably will) cause your machine to become unbootable. And then you’ll have to call the man from PC World. And believe me, you don’t want that to happen.
Look through your BIOS menus, and find a list of drives (you might find one in the boot order configuration). Look at where you’ve attached your new disk, and look for the capacity of the new disk.
If the figure is up to 30gB below what was advertised (remember that 1G is 1024M, not 1000M) then you’re probably OK. But if it’s drastically less (eg my 320gB drive was stated by the BIOS as being 136gB) then your BIOS probably only sees the first n gB of disk space - the rest it is completely blind to.
This means that the BIOS cannot read any partition spanning more than the first 136gB of the disk. Otherwise it returns a disk read error, and will stubbornly refuse to boot.
How, then, do you get the machine to work?
The way I have my disk partitioned is roughly 99gB of space for the OS and programs. The rest is mounted on drive J and reserved for documents (it’s where my My Documents folder is mapped). In other words, you can still use that full 300gB of space, but only 136gB for the OS.
Otherwise your poor BIOS gets confused and has to suffer Mr PC World poking around at it.
And it may decide to stage a twenty-four hour lightning strike over pay and working conditions if that happens. Like a certain public sector worker’s union whom Gordon Brown feels can be left to starve as long as inflation is kept in check.
