Peripheral Vision

By Mafth tyeliowd.

AN OVERVIEW OF THE DOS THAT POWERS CMD DEVICES

CMD DOS () is the locations and commands are emulated onall control program built into CMD's HD, FD, CMD devices, and a special extended and RAMLink which is responsible for "Native' Job Queue is also provided. Fast controlling all operations related to these serial 'Burst' commands arc supported on devices. The DOS interprets commands from the HD and FD. the computer and responds byperforming Commands arc sem n> CMD devices in [he requestedoperation (load, save, format, the usual manner (over ihc Command etc.). The DOS breathes life into CMD Channel; Secondary Address 15). The Error devices; without it, our equipment woulddo Channel is also accessed in the same manner little more than take up space on your as with other Commodore diskdrives. Files computer desk. Of course, this is also true are opened and closed and file data is for Commodore disk drives (such as the accessedthrough the normal BASIC 1541,1571 and 1581) which, like CMD HD commands or Kernal routines. The directory and I'D drives, arc "intelligent" and contain structure of CMD devices is the same as an on-board microcomputer which by nature Commodore disk drives and directories can requires a control program (DOS) to be viewed by using the standard commands. function. RAMLink, instead ofhaving its and use if just like your other Commodore Commodore wildcard and pattern matching own microprocessor, uses the C-64 or C-12H disk drives. Even RAMLink, which plugs syntax is supported aswell. microprocessor to perform its functions and directly into the computer's Cartridge Port, The close adherence to Commodore DOS in that respect can also be regarded as an appears as a disk drive, eventhough standards makes CMD devices compatible intelligent device. programs and files are being accessed from with nearly all C-64/128 software and The FD and RAMLink (like Commodore a solid-state RAM disk. eliminates the need for program disk drives) have their DOS programmed All CMD devicessupport PRC, SEQ, modifications. In addition, GEOS onto a ROM (Read-Only-Memory) chip. REL and USR files along with all file- compatibility is provided through special The HD has its DOS stored in a hidden area related commands, including Load, Save, Configure files supplied with the devices or (partition) on the hard drive and is Verify, Open, Close, Scratch, Rename, through CMD's gateWay desktop. downloaded to RAM each time the drive is Copy, and Record Position. Direct Access powered-up. files are supported along with the Block- Partitions Allocate, Block-Free, Block-Read, Block- Because of the large capacity of CMD Compatibility Write, Buffer-Pointer and Block-Execute devices, CMD DOS provides a means of The core of CMD DOS provides an commands. The 'User' commands are also organizing the storage area into manageable emulation of Commodore DOS 1541, 1571 provided: U0. Ul (block read), U2 (block sections. On the FD and RAMLink you can and 1581 commands. This enables CMD write), U3-U8 (jump), UI (warm reset) and divide the overall storage space into as many devices to act and respond like Commodore UJ (cold reset). Memory access commands as 31 segments (partitions), while on the disk drives, which provides the user with a are also included (Memory-Read, Memory- HD, as many as 254 partitions canbe created. familiar command structure along with ;i Wriie, and Memory-Execute), along with Partitioning a CMD device is similar to high degree ofsoftware compatibility. In support for Utility Loader and Autobool dividing a large disk into a number of smaller other words, you can plug in a CMD device Loader files. 1541,1571 and 1581 Job Queue disks and is accomplished through the use

Commodore World 36 April 15, 1994