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*** REMM.SYS INFORMATION HEADLINE *** EPG Products (Memory Boards): ----------------------------- This is a breakdown of AST (EPG) Memory Products which require certain versions of the REMM.SYS Expanded Memory Manager. This is not to be confused with AST Premium Computer System's REMM.SYS drivers. This breakdown does not apply to AST Computer Systems. Product's Name REMM ASTEMM ---------------------------------- Advantage/2-386 N/A 2.27 Advantage Premium 4.30 N/A RAMpage/286 4.30 N/A RAMpage/2 4.30 N/A RAMpage/2-286 4.30 N/A SixPakPremium 4.30 N/A If you are using an application program which requires an older version of REMM.SYS (your software should state this in it's documentation), then you should use an older version - rather than the most recent version. SPECIAL NOTE: You can determine which products REMM.SYS is compatible with by its version number. For REMM.SYS versions 4.0 and later, an ODD version is for AST EPG Memory Boards (i.e RAMpage, Advantage Premium, etc.). An EVEN version is for AST Premium Computer Systems (i.e. the Premium/286, etc.). REMM.SYS v4.3 is for AST Memory Boards REMM.SYS v4.2 is for AST Computer Systems This REMM.SYS identification strategy does not apply to REMM.SYS versions prior to 4.0. If any of these products are installed in an AST Premium computer system, then you should use the REMM.SYS that was intended for use in that particular computer. SYSTEMS (AST Premium Computers): -------------------------------- The following are versions of REMM.SYS that have been released specifically for AST Premium Computer Systems. They are not intended for use with any AST Memory Board (except when the Memory Board is installed in an AST Premium Computer System). Released REMM's for the Premium/286 are: REMM.SYS v4.20 (EMS 4.0 Specification) REMM.SYS v4.00 (See Notes Below) REMM.SYS v3.50 (EMS 3.2 Specification) REMM.SYS v3.00 NOTES: If you are currently using REMM.SYS version 4.00, than you should consider updating your system to the latest version (specifically, version 4.20). This way, you can be assured that you are using the most up-to-date version that AST has available (REMM.SYS version 4.20 is fully LIM-EMS 4.0 compatible). AST Premium Workstations use the same REMM.SYS versions that the Premium/286 does. However, it is designed around LIM EMS v4.0, and thus will not work with any versions of REMM.SYS prior to v4.0. So, if you have an AST Premium Workstation, you should be using the most current version of REMM.SYS that is compatible with LIM-EMS v4.0 (i.e. REMM.SYS v4.20). AST Premium/386 computer systems do not use a REMM.SYS device driver. But rather, it uses a driver called ASTEMM.SYS that converts 80386 Extended memory (linear) into Emulated EMS 4.0 Expanded memory. Thus, REMM.SYS should not be an issue on a Premium/386 computer system. AST FASTboard/386 accelorator boards for the Premium/286 must be used with REMM.SYS version 4.27. This board can not use the general Systems or EPG REMM drivers, do to the special nature of the board. REMM.SYS 4.X AND DESQVIEW 2.XX Users of DESQview 2.01 (or above) may experience system lock-up when using a version of REMM.SYS of 4.10 (or above). The lock-up occurs when running an interrupt-intensive application such as a serial communications program. The reason that this particular combination causes this symptom lies in the fact that the LIM 4.0 functions are being executed in software, requiring a large amount of processing time. This amount of overhead becomes critical when processing time must also be devoted to servicing the stream of interrupts generated by a communications program. Any application that must devote a great deal of time to both expanded memory operations and serial communications will eventually be unable to keep pace and cease to function. It is recommended that those users who operate in this environment and experiencing problems, replace the 4.xx version of the REMM.SYS driver with a 3.xx version. For AST Systems products, version 3.50 of REMM.SYS is recommended. For AST board-level expanded memory products version 3.10 of REMM.SYS will operate in this environment. Those users with expanded memory hardware which fully supports the LIM 4.0 Specification, (i.e., AST RAMpage Plus/286 or AST Premium/286 using Advanced FastRAM), will not experience any of the difficulties outlined here. Please note: It advisable to verify that the correct DESQview configuration and operation procedures are followed. Appendix E in the DESQview Manual contains detailed information about running communications programs. The Magic of Remm ... The Rampage Expanded Memory Manager (REMM) is the device driver that must be included in the config.sys file that allows expanded memory to be used and managed. ALL expanded memory whether EMS or EEMS is invisible to DOS. That is - DOS, cannot acknowledge or test the memory of an expanded memory board. It is the expanded memory manager and the application program that utilize expanded memory. The first expanded memory boards were manufactured according to the Expanded Memory Specification (EMS) developed by LOTUS, INTEL, & MICROSOFT. Only a few months later, AST RESEARCH announced the Enhanced Expanded Memory Specification (EEMS) and began shipping their EEMS boards. EEMS was a true superset of EMS. EEMS had all the same functions as EMS, however, it provided quite a bit more power. When REMM initializes it searches for a 64KB window in the reserved area between 640KB and 1MB. It begins its search at C000 and jumps upward in 16KB increments. When REMM finds four contiguous 16KB segments that are available it creates its 64KB window. If REMM cannot find four consecutive 16KB blocks available it will fail to install itself. REMM cannot see into the future. Should a device or program attempt to use the same address range as REMM, then most likely REMM will crash. It is the task of the user to be aware of what other ROM's or programs make use of the reserved memory between 640KB and 1 MB. As REMM is initialized in the config.sys there are several steps that it performs: 1) Command line parameters are handled. 2) Test to see if expanded memory is in system. 3) Determine level of hardware support for expanded memory. 4) Read Switch settings from the board (if appropriate). 5) Generate internal tables. a) Handle Table b) Allocation Table 6) Test Expanded Memory. 7) Done - Install INT 67. N.B. Boards are checked in Base I/O order. Versions of REMM Due to the continual development of hardware and software, REMM has undergone many changes and will continue to do so for some time to come. REMM was first shipped by AST Research along with their EEMS boards - the Rampage!, Advantage Premium, and Rampage286 to name a few. The REMM driver was bundled along with other software utilities on the SUPERPAK Diskette. At that time in the market place the IBM standard had set the BUS speeds at 4.77 MHz for the PC & XT; and 6 or 8 MHz for the AT. The PC/XT and AT-class EEMS Boards manufactured by AST were made to operate at those respective clock rates. The REMM driver was written specifically with those environments in mind. Over time, enhancements were added to improve overall performance and compatibility. When AST decided to manufacture the Premium/286, they incorporated into its architecture the FASTSLOTS which provided direct access to the microprocessor at zero wait states. To take full advantage of this proprietary architecture a system specific version of REMM was required. The first system version of REMM to ship with the Premium/286 was REMM version 3.5. This version enabled expanded memory according to the EEMS specification. When the LIM 4.0 specification was announced, REMM was subsequently updated to version 4.x. If x were an even number then REMM was specifically updated with the Premium Systems architecture in mind. If x were an odd number then that version was meant for the add-in memory boards made by AST. For best performance, it is important that only a 'systems' REMM be used with AST's system products. This is especially true when using an AST expanded memory card in addition to the FASTRAM card. Premium/286 & REMM version 4.x The address range of E000-EFFF in the Premium/286 is available for use by REMM if and only if: A) The version of REMM is capable of selecting the 'E' block. B) All system memory is located on a FASTRAM card. C) No other device is utilizing that same address range. (i.e. Expansion ROM's or Device Drivers) Video Boards & REMM One of the most common devices that occupy the reserved area between 640KB and 1MB are the various video boards. Below are listed the various video standards and the most appropriate exclusions to use with REMM to avoid any conflict. ________________________ | | | MONO /X=B000-BFFF | | CGA /X=B800-BFFF | | EGA /X=A000-C3FF | | VGA /X=A000-C7FF | |________________________| REMM & AST-3G Cards However, there are now video adapter cards that emulate several modes and may require a different set of exclusions because of their versatility. One good example is the AST-3G Cards. Below are listed the various video modes and the most appropriate exclusion to use with REMM to avoid any conflict. ________________________ | | | MONO /X=A000-C3FF | | CGA /X=A000-C3FF | | EGA /X=A000-C3FF | |________________________| REMM & VGA The new VGA boards are becoming more attractive to the computer world with its larger color palette and improved performance. The AST VGA boards contain ROM's whose address range is from C000-C7FF. Display memory occupies the range from A000-BFFF. The proper exclusion statement would be: ________________________ | | | VGA /X=A000-C7FF | |________________________| <more> There are some VGA boards that are using some memory outside the range set aside for the VGA standard. If this is the case then it would be best to use the following exclusion: ________________________ | | | VGA /X=A000-CFFF | |________________________| N.B. Some VGA boards are 16 Bit Cards. Please see section - REMM in 16 Bit Mode. REMM - Networks - Emulation Boards Network & Emulation Boards can present a very interesting environment for REMM. For the most part, most of these boards contain ROM on them that allow for self-diagnostics and initialization. The ROM must be accessible to the microprocessor and so usually occupies a small range of memory above 640KB and below 1MB. It is important to determine where that ROM resides and to make REMM avoid it by use of the proper exclusion parameter. If the manufacturer of the expansion board allows the ROM to be addressed at various locations then that aids in making all these devices work together in harmony. However, once the config.sys has been installed , these boards may require a window of memory so that they can pass data. REMM may have installed itself successfully but may have been corrupted by another intruding memory window. It is most important that the system integrator be aware of the memory requirements of all devices. REMM in 16 Bit Mode It is only in light of recent technical advances that the current subject be discussed. There are now in the marketplace video boards that operate in 16 Bit mode. This is done to increase the performance of video in a system. While this is a great benefit, it requires a bit of thought in using REMM. REMM can operate in either 8 Bit or 16 Bit mode. REMM has always defaulted to 8 Bit mode but may be used in 16 Bit mode by use of an undocumented parameter - /M. REMM can only be used in 16 Bit mode if it is in a 128KB segment by itself or sharing it with another 16 bit device. 8 bit and 16 bit devices cannot occupy the same 128KB segment. When you break up the 1MB of addressable memory into 128KB segments, there are a total of eight segments divided as follows: _____________________________________ | | | 128KB Segments Binary (default) | |_____________________________________| | | | E000 - FFFF 0 | | C000 - DFFF 0 | | A000 - BFFF 0 | | 512 - A000 1 | | 384 - 512 1 | | 256 - 384 1 | | 128 - 256 1 | | 0 - 128 1 | |_____________________________________| The eight segments are assigned a binary digit that comprise one byte. The eight bits of 00011111 can be converted to the hexadecimal number of 1Fh. This is the default mode of REMM which recognizes 0 - 640KB as being 16 bit accessible memory while the area above 640KB and below 1MB are accessible in 8 bit mode. In order to access a segment in 16 bit mode just place a one in the segment that needs to be accessed in 16 bit mode. Convert the new binary number to a hexadecimal number. This is the number that will be used with the /M.parameter. EXAMPLE: Using an AST-VGA+ video adapter (16 bit card) and REMM, the proper statement in the config.sys file would be: _______________________________________________ | | | DEVICE=REMM.SYS /M=7F /X=A000-C7FF /S=C800 /N | |_______________________________________________| REMM will now operate in 16 bit mode and reside in the same segment as another 16 bit device - the AST-VGA+ video adapter card. Conclusion In the early days of computing with the IBM PC, life was very simple. If you had an empty expansion slot and an expansion board it was easy to upgrade your system. Drop the board in and power up the CPU. Now however, with more boards and the complex requirements made upon the operating system, more thought will be needed to fine tune the micro- computer to the specific tasks required by the user.