DOCUMENT ID: 1136-02 SYNOPSIS: Selecting CD-ROM blocksizes for different filesystems OS RELEASE: PRODUCT: Solaris x86 KEYWORDS: CDROM blocksize filesystem configure device driver DESCRIPTION: When installing x86, my system cannot read the data from my CD-ROM even though it is configured properly and works with other applications. SOLUTION: UNIX device drivers for block storage devices have traditionally been buffered at 512 bytes per logical block, as in the Sun OS. The common CD-ROM drives on the market, however, default to a more optimized block size of 2048 bytes per block. If the drive is not capable of auto-sensing the block size of the media or cannot accommodate 512 bytes/block, it may not be usable under Unix. Special or OEM specific firmware, pass thru drivers, or DOS utilities can invoke a change at the SCSI CDB level in a specific mode-select page to explicitly set the desired block size. The latest version of Solaris x86, for example, is able to install from most SCSI II compliant CD ROM drives off the shelf and un-modified. At a native block size of 2048 bytes per block, the old limitation of requiring a 512 byte device no longer exists to install Solaris x86. Depending on the CD ROM drive you are using, however, you may have to explicitly set the buffer size on the drive after the power has been turned on. The easiest way to do this is to use a DOS/SCSI utility like Compaq's EZ-8, Wangtek's RX1, or the public domain program "CDBLKSIZ.exe" that is available off the Usenet and DOS BBS's. DATE APPROVED: 10/10/95