CDrive CD ROM-Filesystem for AMIGA Computers 1. Introduction CDrive is a CD-ROM Filesystem for the Commodore Amiga and currently supports the formats ISO 9660 Level 1, Level 2, Rockridge and High Sierra. By use of it's configurable Cache Parameters, or with the use of DynamiCache, very fast CD data access will be possible. Since CD-ROMs usually would be used on different platforms, in 1985 the High Sierra format was laid out, which sometime later with a few changes, came to be known as ISO 9660. In order to access the data of an ISO 9660, you must install a file system, since ISO 9660 is completely incompatible with the Amiga File System. A file system, thus, provides the interface from the File/Directory structure of a device to the known AmigaDOS File/Directory functions. A CD-ROM is always write-protected, so that all read/write operations are not effective and a "Disk Write Protected" error will be given in case of write acesses. 2. CDrive Installation CD-ROM First you should always read the documentation of the CD-ROM device you are using. Next, you must select an unused SCSI-ID for the CD-ROM and connect it to your Fastlane Z3 controller by follwoing the instructions for internal or external connection. File System On the Fastlane Z3 disk, in the CDRom directory, you will find an icon with the name InstallCDrive. Double click on this icon, and the installation will be done automatically (the file "CDrive" will be copied to your l: directory, some predefined mountlists will be copied into your devs: directory, and the zdx: icons for mounting a CD-ROM from the Workbench will be copied into your devs:dosdrivers directory). Now enter the SCSI-ID of your CD-ROM device either into the "unit" parameter of the mountlist you want to use or if you want to mount your CD- ROM from the Workbench, enter this SCSI-ID in the Unit entry for the ZDx: Icon in the devs:dosdrivers directory. To activate the file system, there are different possibilities: a. You can type in the Shell "mount zdx: from devs:mountlist.zdx". b. You can insert the command "mount zdx: from devs:mountlist.zdx" into the file user-startup in your s: directory. c. You can mount your CD-ROM device by double-clicking on one of the ZDx: icons, which are copied into your devs:dosdrivers directory. For more information on how to mount a device, using the mount command and the user-startup file, please refer to your Amiga DOS manuals. A typical mountlist for a CD-ROM will look like this: ZD0: Name of the handler Device = z3scsi.device Name of the SCSI Device Unit = 3 ID of the SCSI Device Buffers = 40 See section below regarding Cache Entries Flags = 0 See system manual FileSystem = l:CDrive Name and directory path of Filesystem BufMemType = 5 See system manual Mask = 0xfffffffc Only used in Cache Mode 0x0 GlobVec = -1 See system manual Mount = 1 See system manual Reserved = 0xffffffff See section below regarding Format Entries LowCyl = 40 See section below regarding Cache Entries HighCyl = 4 See section below regarding Cache Entries Surfaces = 0x0 See section below regarding Device Entries BlocksPerTrack = 0x1 See section below regarding Cache Entries Priority = 10 See system manual StackSize = 6000 See system manual # Format Entries Reserved The mountlist entry Reserved can be used to enter important flags for the Rockridge format. The Rockridge format is an extension to the ISO format and is mainly used in the Unix world. One of it's advantages is the possibility to define longer names than ISO Level 1. The normal user should also leave the Reserved value unchanged. Rockridge 0x80000000 switches the Rockridge Extension globally on Rockridge_Name 0x00000001 activates the Rockridge name extensions Rockridge_Date 0x00000002 activates the Rockridge date extensions Rockridge_OtherRights 0x00000004 activates the Rockridge OtherRights extensions Rockridge_GroupRights 0x00000008 activates the Rockridge GroupRights extensions Rockridge_OwnerRights 0x00000010 activates the Rockridge OwnerRights extensions Rockridge_UserID 0x00000020 activates the Rockridge UserID extensions If set to zero, ID0 will be used. Rockridge_GroupID 0x00000040 activates the Rockridge GroupID extensions If set to zero, ID0 will be used. --- Cache Entries The CDrive currently offers two cache modes, which can be selected with the mount entry BlocksperTrack. a. BlocksPerTrack = 0x0 This mode is the best for users who most often access the CD-ROM via Shell commands. The memory usage of the cache will determined by the formula (Buffers+LowCyl+HighCyl) * 2048 = used bytes - Buffers This value determines the number of buffered directory blocks. - LowCyl This value determines the number of sectors which will be read-ahead when .info files are accessed. The reading of icons is sped up significantly by this read-ahead caching. - HighCyl This value determines the number of sectors which will be read-ahead when small files are accessed. The reading of small files is sped up significantly by this read-ahead caching. b. BlocksPerTrack = 0x1 In this mode, when a read access on the device is executed, it will first be checked whether a data block is already in the cache. If the block is not in the cache, a certain number of sectors will be read-ahead; this number can be determined by the HighCyl entry. This caching mode is the best for users who usually access the CD-ROM from the Workbench. The memory usage of the cache will be determined by the formula Buffers * HighCyl * 2048 = used bytes - Buffers Determines the number of static cache blocks. A cache block consists of a certain number of sectors, which is determined by the HighCyl entry. - LowCyl Is not used in this caching mode. - HighCyl Determines the number of sectors in each cache block.