Thinkpads Forum

Hi

Just got myself a T42 2374-K1G and the HDD fitted is a Toshiba MK4026GAX. According to merchants selling this on the web this is a 40Gb HDD, which is what the ThinkPad website states the 2374-K1G should have. However, under My Computer it shows up as a total size of 32.6Gb with 26.0Gb free space. Any ideas why please?

Thanks

Not ALL GBs are equal!

HD merchants and manufacturers frequently report HDs in 1K bytes = 1MB increments, when in fact 1024bytes = 1MB! Ergo, rather than dividing a HD's capacity by 1K to obtain the amount used vs. free, Windoze (and many other OS front ends) divide the HD by 1024 and report the results. So your HD is starting out at ~37GB when reported in this manner.

By the time you deduct the hidden partition for the OS recovery software as well as IBM rescue and recovery, you're down to ~32GB to 36GB of usable HD space.

Regards,

James

Marketing uses base 10 to advertise storage capacity, but computers are naturally base 2 (i.e. binary) machines, so you lose out some capacity just on semantics. In other words, a "kilo" in normal terms is 10^3 = 1000. In computer terms, a "kilo" is actually 2^10 (1024).

So "40 GB" in base 10 (i.e. actually 40 * 10^9 bytes) is really only 37.25 GB in base 2 (i.e. 37.25 * 2^30 bytes). You can plug this into a calculator to verify this.

The other storage is probably lost to the IBM recovery partition (the thing that lets you push the Access IBM button and just instantly restore the disk to its factory settings if you have a problem). You can remove this partition if you make your own set of rescue CDs.

Many thanks

Yep, hadn't thought to check that. I just assumed that the capacity stated by the manufacturer was the same that I would see in Windows because that has been my experience in the past, with laptops I have bought. But then these were pre-10Gb HDD days so, within the range of error, different calcs would make a marketing 4Gb also show as a Windows 4Gb.

Anyway ...

I just checked the more detailed capacity info under "properties" and here are the details:

The Toshiba website states formatted capacity 40,007 MByte. When I divide this by 1.024 I get 39.069. However, when I check in Windows the capcity is shown as 35,060,948,992 bytes and 32.6GB. The 35.... is roughly 1.075x 32.6, and neither are anywhere close to 39.069 or 40.007. And the 1000 to 1024 conversion does not seem to figure in any of the 3 figures stated by Toshiba or Microsoft. Of course, 1.024^3 is 1.074, which is close. But if the conversion does involve a cube of 1.024, why?

The 35 ... and 32.6 figures are before subtracting the space for IBM Recovery, which takes them down to 27,973,451,776bytes and 26.0GB.

Its so long since I studied computers that I can't figure out any reason for there to be capacity discrepancies other than the 1000/1024 issue.

Any more ideas please?

Thanks

Mike

Didn't scroll enough there. OK, so the ratio of 10^9/2^30 accounts for the 35.../32.6 ratio shown in Windows . Which leaves the 40.007 stated by Toshiba ..... ?

The Rescue and Recovery portion of the hard drive is completely hidden from Windows. This is because the BIOS reports to the operating system fewer cylinders on the hard drive than the hard drive actually has. So Windows will never show the full capacity of your hard drive. More info on this link.