18 December 1994 **SCSI README** This version of MDOS (2.50S) is backwards compatible with MDOS 2.21 and GPL 2.0. It contains the following enhancements- Support for SCSI hard drives similar to HFDC hard drives Up to 3 SCSI hard drives of 256 MB each Co-existance of an HFDC, FDC, HRD, PFM, GenMod and SCSI card. Requirements for use - In order to use MDOS 2.50S with a SCSI card you need to have the folowing: Extra 32k FAST RAM SCSI Card at CRU base >1200 SCSI HD at ID 0, 1, or 2 Nothing extra is required to use MDOS 2.50S with a non-scsi system. Follow the guidelines provided in the WHT SCSI users manuals for installing and setting up the SCSI card. Plug in the provided MDOS Power-up EPROM (provided with shipments of MDOS 2.50S to current SCSI owners), and format your drive using MYS included in this archive. Please note that until the TI DSR for SCSI is complete you will not be able to BOOT from your SCSI HD. Follow the instructions with MYS for formatting the SCSI hard drive. If you are using SCSI without an HFDC add the following line to your autoexec: HARD OFF This will disable HFDC hard drive access, and is necessary for proper operation of SCSI without an HFDC. Once you've formatted SCSI, add the appropriate ASSIGN statement to your autoexec to assign the SCSI drives to letters. For example: ASSIGN C=SCS1: Valid SCSI device names are SCS1, SCS2, and SCS3 for the 3 hard drives. Use these names to access the SCSI drives from GPL. Default ASSIGN values for SCSI are H, I, and J and can be viewed by typing ASSIGN from the command line prompt. You are now ready to use DIRECTORY MANAGER to create directories and copy files to the SCSI drive. **A Note about compatibility. Most programs that allow hard disk access are hard coded to WDS. However, many of these can be sector editied to change the WDS references to SCS to allow them to access SCSI instead. There are limitations to this however. Some GPL programs require a device to have DSR LEVEL 2 access routines, and at this time SCSI does not. This means that some programs like TELCO for example will not be able to take fulladvantage of SCSI. (Telco cannot up/download to/from SCSI, but can be boot and ran from it). DO NOT USE /r OPTION FOR EXEC 2.21 WHEN RUNNING PROGRAMS FROM SCSI!! The EPROM provided is not a complete one and HAS NO SCSI SUPPORT BUILT IN at this time, it is just a power-up program. DO NOT USE CYA for MDOS 2.21 on MDOS 2.50S. Obtain an update from Tim Tesch. Currently FORM3MEG does not correctly copy all of MDOS 2.50S to the RAM DISK. To correct this problem, run FORM3MEG and install 2.50S as usual, but BEFORE REBOOTING, delete the copy of MDOS from the ramdisk and re-copy it manually using Directory Manager. If you do not do this the Geneve will lock up on power-up. UTILITY PROGRAMS INCLUDED- MYS - Manage Your SCSI, Mike Maksimik & Tim Tesch, formats SCSI HD's SDM - SCSI Disk manager, Brad Snyder, current version formats SCSI HD's and sector edit's them, future version will be complete disk managers. SCSIBACK - SCSI Back up utility, Mike Maksimik, allows you to copy and MDOS device directly, sector my sector, to any SCSI device. Allows quick verification of hardware functionality, benchmarking and easy way to copy SAME SIZE HFDC Hard disk over to a SCSI drive. SCSIREST - SCSI Restore utility, Mike Maksimik, restores a SCSIBACK backup. Each of these programs has easy to follow on-line instructions. ** Future enhancements to MDOS & SCSI ** Currently SCSI does not support the FC-1 floppy disk controller, this is planned. This format will be a "mini-hard drive" format with HFDC hard drive like structure. Sizes of 2.88, 1.4, 1.2, 720 and 360k will be supported. A utility program to convert TI and MS-DOS disks will be provided as well. DSR LEVEL 2 access will be added to SCSI in MDOS providing programs like TELCO direct access to the SCSI hard disks. PARTITIONS are planned to expand the capacity of the SCSI drives from 256 MB each to more than 1 GB each. WHT would like to thank the dedicated efforts of Mike Maksimik, Tim Tesch, Brad Snyder and Jeff White. Without them, SCSI would not be a reality.