1. About AHCICDU is a DOS CD/DVD optical disk driver based on Rudolph R. Loew's AHCICD driver. 2. Installation AHCICDU.SYS has to be added to CONFIG.SYS: DEVICE=AHCICDU.SYS /D:name [/Q] [/C:controller] The /D option is - as in all optical disk drivers - required to set the "device" name. With option /Q no banner is displayed. Option /C might be used to select the AHCI controller to scan for ATAPI devices. The default is the first, which would be /C:0. 3. Features - Sector buffer in extended memory, so a pretty low DOS-memory footprint (1 kB). - AHCI tables ( command list, FIS receive buffers, command table ) are relocated to extended memory, so it should be possible to move the XBDA. - doesn't rely on the (optional) Serial ATA Capability register set ( IDP mechanism ) and hence should work with any AHCI device. 4. Requirements/Restrictions - AHCICDU uses unreal-mode to access the memory-mapped device registers, hence it can't work in v86-mode. - an installed XMS host is needed to allocate extended memory for the driver's sector buffer and AHCI tables. - only "cooked" reads are supported - no support for Audio CDs. - max. 6 CD/DVD devices are supported.