The first iBook came with a 3 GB HD, which was a fair balance because MacOS needed only 500 MB space. The next revision in February 2000 had a 6 GB HD installed, the final second Edition sported a 10 GB drive.
You will regognize these ancient drives by their loud operating noise. If you want to replace them, there is no need to buy a superfast 5400rpm model, because the old controller hardware is not a speed demon in any way. Be sure to buy a standard IDE harddrive - U-ATA or perallel ATA, (not the new S-ATA standard) with a height of max.9,5mm. The controller is able to handle partitions up to 128GB.
You can buy a 160GB drive anyway e.g. a Samsung Spinpoint M5P 160GB (HM160HC), which results in a formatted 128 GB Volume. A standard 120 GB drive is only 111 GB formatted.
You will need to dismantle your iBook almost completely , there a more than 40 screws to go. Take a look at Ifixit.com for a good tutorial with a screw guide.
|Announced in July 1999 at Macworld New York, the iBook was perhaps the most anxiously awaited Apple computer ever. Aimed at the same consumer market as its big brother, the iMac, the iBook filled the 2x2 consumer/pro/desktop/portable matrix that Steve Jobs had first detailed more than a year earlier.
30 years of Apple Products, wired.com