CDR-1000 (250-1077) Software Installation Addendum Faxback Doc. # 5268 Memmaker and CD-Rom Drivers for the CDR-1000A Discussion: If you have an MPC Computer using a CDR1000A CD-ROM, and you load the MTMCDD.SYS Driver and MSCDEX.EXE MPC Extensions driver files high, will your CD-ROM work? This question was asked of several different folks. Let's start with the first MPC computers that Tandy shipped years ago. These machines, I.E. 2500 SX/16/20/25 MPC Computers, etc, had a Soundblaster board and a CD-ROM interface board installed in them. Let's talk about the CD-ROM interface board. This board is an 8-bit board. This board comes with its own utilities/install diskette. The name of the CD-ROM driver file is MTMCDD.SYS. This is an 8-bit driver file. This driver can be loaded high by using the DEVICEHIGH statement in the CONFIG.SYS file. Also on the utilities diskette is a file called MSCDEX.EXE. This is a MPC extensions driver file. This file can also be loaded high by using the LOADHIGH command in the AUTOEXEC.BAT file. There is another file on the utilities diskette called MTMCDD.SYS. This file is also a CD-ROM driver. The difference between MTMCDD.SYS and MTMCDS.SYS is: The MTMCDD.SYS driver uses DMA and IRQ to transfer data. The MTMCDS.SYS driver uses Programmed Input/Output, or PIO. If the MTMCDS.SYS driver is used, the data transfer rate will be significantly slower. You can also load the MTMCDS.SYS driver file high. Next, the later MPC computers, I.E. TFD's, 486's etc. plus the MPC upgrade kit, came with a 16-bit Tandy MPC board CD-ROM interface. This board is a 16 bit board. This board requires a 16 bit CD-ROM driver. The name of this driver is also MTMCDD.SYS. This driver will NOT repeat NOT work if you load it high. NOTE: There is no MTMCDS.SYS for the one board MPC system. The MPC extensions driver, MSCDEX.EXE, can be loaded high. MS-DOS 6 has a new version of MSCDEX.EXE, version 2.22. This version is not in DOS 6's SETVER table. It does not need to be. This version will also work with DOS 5. You can locate this file in the DOS subdirectory of a MS-DOS 6 Computer. SUMMARY: The 8-bit CDR1000A interface board that comes with a two board MPC computer, can utilize two different CD-ROM drivers along with the MPC extensions driver file. They are: MTMCDD.SYS - 8-Bit CD-ROM Driver File - Can Be Loaded High! - DMA MTMCDS.SYS - 8-Bit CD-ROM Driver File - Can Be Loaded High! - PIO MSCDEX.EXE - MPC Extensions File - Can Be Loaded High! The 16-bit Tandy MPC board on the newer MPC computers can utilize one CD- ROM driver along with the MPC extensions driver file. These files are: MTMCDD.SYS - 8-Bit CD-ROM Driver File - Can NOT Be Loaded High! MSCDEX.EXE - MPC Extensions File - Can Be Loaded High! FURTHER DISCUSSION: All of this talk of loading drivers high, brings up another consideration, that must be told. Let's talk about MS-DOS's Memmaker program. For some reason or another, our customers who ventured into the realm of DOS 6, seem to think that Memmaker is an intelligent program. It is not. Memmaker looks at the CONFIG.SYS file and the AUTOEXEC.BAT file for drivers and TSR's to load into upper memory. This is an attempt to free up system RAM (640K). When you operate an MPC single board system, install MS-DOS 6, and run Memmaker, the program will load both MTMCDD.SYS and MSCDEX.EXE high. I mentioned earlier in this discussion that this will not work. There are two ways to stop Memmaker from loading MTMCDD.SYS high. 1. Before you execute Memmaker, go to the DOS subdirectory, and type, EDIT MEMMAKER.INF then press . Follow the instructions on the screen. They will tell you how to add MTMCDD.SYS to the exclusion list so that Memmaker will ignore MTMCDD.SYS and not load it high. 2. Execute Memmaker, go to the second screen where it asks you if you want to run Express Setup. Press the space bar to change to custom setup, then press . The first question on the screen, will ask if you wish to choose which drivers to load high. Press the space bar to change to YES, then press . Continue Memmaker's install procedure and you will be asked to select the drivers you wish to load high. Do not select MTMCDD.SYS. Memmaker will now configure your RAM correctly. (dtc-08/02/93)