Whilst it does 'work', the Microsoft RAMDISK.SYS driver included in Windows XP is next to useless. First, it's limited to 32Mb (although the RAM disk driver included in XP Server 2003 can support 512Mb (the absolute limit when used with NTLDR / NTDETECT) so it might be possible to get more than 32Mb). Second, all Microsoft's RAM disk drivers are limited to 'Windows RAM'. For Windows XP (32bit), this means the RAM that Windows itself is permitted to access by the MS 4Gb address Licence limit. To get access any of the RAM that was 'mapped out' by the BIOS (to make way for the i/o devices) to addresses beyond the 4Gb Licence limit, you must use a 3rd party RAM disk driver. As usual, if you want to do anything even slightly 'clever', you must ignore the Microsoft 'toy' offering and go find some real software