Lost in space
I've installed an extra 40GB hard drive. It works but the Properties sheet says total storage is 31.4GB. What's happened to the rest?
Martin Smith

Jack Schofield replies: Drive manufacturers use decimals (base 10 numbers) when selling storage, where 1K is 1,000 bytes and 1GB is 1,000,000,000 bytes (10 the power of 9). Computers work in binary (base 2 numbers), where 1K is 1,024 bytes and 1GB is 1,073,741,824 bytes (2 to the powere of 30) or 1,024 megabytes. You should therefore expect your "40GB" drive to store 37.25GB of data. However, some computer BIOS (Basic Input/Output System) chips have problems with drives larger than 32GB, and your hard drive may have a jumper setting that limits the start-up capacity to 32GB. You could avoid this by changing the jumper, upgrading the BIOS or partitioning the drive to create two smaller drives.

If using a New Technology version of Windows (NT, Windows 2000 or XP), it will not let you create a partition larger than 32GB using the old FAT (File Allocation Table) disk formatting system. This is by design: Microsoft recommends using the NTFS file system instead. You could format a larger drive under Windows 9x/Me and use it under XP but this is not a useful tip unless you use both types of Windows on the same PC. For more information, see the Microsoft Knowledge Base article number 314463, Limitations of the FAT32 File System in Windows XP.

Big Windows
When I look at the Properties of, say, the Windows folder, it says the Size is 576MB (604,366,204 bytes), and the Size on disk is 1,291,386,880 bytes, with 27,300 files in 317 folders. Does this mean that Windows is using up 1.29GB, and is there a way of reducing it?
Andrew Berkerey

JS: When a hard drive is formatted, it is divided into sectors, and when a file is stored, it is written into these sectors. Each file takes up at least one disk sector, no matter how small the file, and no matter how large the sector (or, more accurately, cluster of sectors).

In your case, the properties sheet is showing a huge amount of wasted space. Windows is holding 576MB of data but is taking up 1.2GB of the drive. This suggests that your drive is using large sectors (probably 32K) and that you have a lot of small files. You can see this effect if you right-click on the Favorites folder and select

Properties. My Windows Me machine has 602 links for Favorites, taking up 141K; but because each link occupies a 32K slot, the directory uses 19MB of drive space! Bear in mind that the Windows folder contains more than just Windows files. The Temporary Internet Files and Cookies folders often have large numbers of small files, and you may have lots of files from other programs in the C:\Windows\System folder and, particularly, in C:\Windows\Application Data, which usually includes Outlook Express email. This makes it impossible to give a "correct" size for the Windows folder, though I would expect it to be closer to 1.2MB than 600MB.

There is no failsafe way of cleaning out the Windows directory that saves a significant amount of space. I usually do it by reformatting the hard drive and re-installing everything from scratch. This is not a good idea unless you have complete back-ups and know what you are doing. Also, since hard drive space now costs about £2 per gigabyte, this is not necessarily a cost-effective approach.

How much?
I'm selling my PC to my parents, but I'm not sure how much to ask. It is a Packard Bell Pulsar C433 (433MHz Celeron processor, Windows 98), which cost £850 in 1999. I have also upgraded the memory and graphics card and added a DVD drive.
Chris Whalen

JS: The second-hand value of a PC bears no relation to the original cost, but is capped by the price of new machines. Since you can now get a fast Pentium 4 PC with Windows XP for less than £500, it is hard to get more than about £250 for the average second hand model, and old machines are typically worth half that. To find the "going rate", try eBay. Check the small ads in your local paper and compare with websites such as PC Depot Online.

Backchat

· Last week, Phil Slade asked about copying websites to CD for a school in Kenya with no internet access. John Loader says: "May I suggest a visit to www.worldspace.com? Worldspace operates satellites that, in addition to providing around 40 channels of free radio, have a download-only internet service covering large areas of general information."

· Geoff Winterman wanted to synchronise his PC to an external drive for back-up purposes and I suggested Second Copy 2000 ($29.95 from www.centered.com ). Robert Gray suggests Mehul's Backup, which is free. John Haggerty uses Replicator from, also free, and you can download the source code. Tom Corcoran says: "I use the excellent freeware BASK which will cover all synchronisation backup needs."

· Jamie Keddie wanted software to control a TV set from his Mobile Action MA620 infra-red device. Michael Salem points out you can do it with the Spitfire II.