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Text File | 1990-05-22 | 19.0 KB | 450 lines

-------------- ** EXTENDER ** -------------- Version 1.30 by KEY SOFTWARE PRODUCTS 440 Ninth Avenue Menlo Park, California 94025 (415) 364-9847 Revised: May 20, 1990 ----------------------------------------------------------------------- *** NOTE: See LICENSE.DOC to find out how to access ALL 384k of memory! ----------------------------------------------------------------------- 1. INTRODUCTION ---------------- EXTENDER is a collection of software that can add up to 384k of memory to your 286, 386, or 386SX machine by taking advantage of those motherboards that use one of the following memory controller chips manufactured by Chips and Technologies: 82C302 - Used with 386 Systems without a Cache 82C307 - Used with 386 Systems with a Cache 82C212 - Part of the NEAT Chipset for 286 and 386 82C812 - Part of the NEAT Chipset for 386SX EXTENDER does this by using the 384k of high memory (in the 640k-1MB range) that is on your motherboard but which is normally only used for Shadow RAM. With EXTENDER, this memory can also be used for TSR's, TSR marks, device drivers, and RAM disks rather than loading them into conventional memory (0-640k) where they use precious DOS memory space needed by your application programs. If you don't have an EGA or VGA, or if you don't use graphics, then conventional memory (available to application programs) can be extended from 640k to as much as 736k. Other system requirements: DOS 3.0 or higher, 1M or more of (physical) memory. ---------------------- IMPORTANT DIFFERENCES! ---------------------- EXTENDER has four significant advantages over other DOS Extenders: 1. EXTENDER doesn't require a 386. Other DOS extenders won't work on 286 systems. The only hardware required by EXTENDER is the Chips and Technology chipset and 1MB of hardware. 2. EXTENDER doesn't use any 386 protected mode software. This means that unlike some other DOS extenders, EXTENDER works well with Microsoft Windows/386. 3. EXTENDER doesn't require any extended memory (above 1MB). Other DOS extenders depend on the 386 processor's ability to remap physical memory from above 1MB into high memory, but of course that memory is no longer available as extended memory. 4. EXTENDER, unlike all other DOS extenders, can use the high memory addresses that coincide with the Bios ROM or any adapter that you have installed. A device driver is supplied with EXTENDER that uses bank-switching techniques to gain access to this memory. This gives EXTENDER the unique ability to use *ALL* 384k of high memory! 2. INSTALLATION --------------- You should first install EXTENDER on a floppy to verify that you can boot and operate your PC reliably with EXTENDER installed. To install EXTENDER on a floppy, do the following: Step 1: Use the FORMAT command with the /S option to prepare a bootable floppy disk. Step 2: Copy the files EXTENDER.SYS, HIGHDRVR.SYS, HIGHTSR.EXE, HIGHMEM.EXE, COLS.40, and COLS.80 to the floppy disk. Step 3: Copy the DOS files PRINT.COM and ANSI.SYS onto the diskette. Step 4: Create a CONFIG.SYS file on the floppy that contains the lines: DEVICE=EXTENDER.SYS ? DEVICE=HIGHDRVR.SYS ANSI.SYS The "?" in the first line is intentional - it directs EXTENDER to display what it finds in the high memory address space. (For other device drivers that require command line arguments, simply place those at the end of the "DEVICE=" line.) Step 5: Create an AUTOEXEC.BAT file on the floppy that contains the single line: HIGHTSR PRINT /D:PRN Step 6: Boot from the floppy. If everything goes ok, you'll see a sign-on box that looks something like the following: +-------------------------------------------------------------------+ | EXTENDER v1.30 - For Chips & Technology (tm) Memory Controllers | | Copyright (C) 1990, Key Software Products, All Rights Reserved | | Access Key # 00000000 licensed for EVALUATION ONLY | +-------------------------------------------------------------------+ | Memory locations A0000-BFFFF (128k) are EGA Display RAM. | | Memory locations C0000-C3FFF ( 16k) are ROM Bios Code. | | Memory locations F0000-FFFFF ( 64k) are ROM Bios Code. | | ROM at C0000 copied to Shadow RAM. | | ROM at F0000 copied to Shadow RAM. | +-------------------------------------------------------------------+ | Memory Available: 640k DOS, 32k High Memory, 32k Bank-Switch. | +-------------------------------------------------------------------+ If your PC stops before displaying the entire box shown above, or if it fails to operate properly after booting, this is because EXTENDER failed to identify one of your installed adapters that uses some portion of the high-memory address space. If this happens, you'll need to use the command line options (discussed below) to manually disable the corresponding region(s) where conflict occurs. When AUTOEXEC.BAT is invoked, you'll see the following on your screen which verifies that PRINT has been installed: A>HIGHTSR PRINT /D:PRN Resident part of PRINT installed PRINT queue is empty A> If you like, you can try using the PRINT program to print a file. Now run HIGHMEM to get a map of high memory. It should look something like this: MCB Address Range Bytes Description Mark Switch ---- ------------- ------- --------------- ---- ------- None A0000-C3FFF [147,456] A0000-BFFFF 131,072 EGA Display Ram 131,072 C0000-C3FFF 16,384 Shadow Ram 16,384 C400 C4010-C436F 864 EXTENDER.SYS C437 C4380-C551F 4,512 ANSI.SYS C552 C5530-C6BCF 5,792 PRINT.COM C6BD C6BE0-EFFDF 168,960 -- Free -- EFFE EFFF0-FFFFF [ 65,552] F0000-FFFFF 65,536 Shadow Ram 65,536 ------- ------- Free DOS High Memory: 168,960 Bank-Switch Free: 212,992 Largest Free Block: 168,960 Max Contiguous: 147,456 Numbers enclosed in brackets (e.g., "[147,456]") are not included in the totals. The column labelled "Mark" is used in conjunction with HIGHMARK and HIGHUNDO. The column labelled "Switch" shows which entries can be used as Bank-Switch memory for a ramdisk or for TSR marks. If you wish, you can verify that ANSI.SYS is installed and operating by using the commands: TYPE COLS.40 {switches display to 25 rows by 40 columns}, or TYPE COLS.80 {switches display to 25 rows by 80 columns}. (These commands will display garbage on the screen if ANSI.SYS has not been installed.) 3. COMMAND LINE OPTIONS FOR EXTENDER.SYS ---------------------------------------- There are only three command line options for EXTENDER.SYS: "?", "-", and "+". The first of these ("?") directs EXTENDER to report what it finds installed in the high-memory space. It will automatically detect the memory space used by most display adapters, such as monochrome (MDA and Hercules), CGA, EGA, and VGA. It will also detect any Bios ROM's, or any RAM which reads back exactly what has been written. Some adapters, however, may implement write-only RAM or RAM which doesn't read back the same. In these cases, the "-" option is required to prevent EXTENDER from trying to use that memory space. The format of the "-" option is: -<base>:<size> where "<base>" is a base paragraph (segment) address expressed as four hexadecimal digits, and "<size>" is kilobytes expressed in decimal. For example, to prevent EXTENDER from using the 10k address range starting at segment E400, the proper option syntax would be: -E400:10 The format of the "+" option is identical, except for the leading plus (instead of minus) sign. For example, to force EXTENDER to use the 2k region starting at segment A780, the proper option syntax would be: +A780:2 There are some restrictions on these options: (1) The base must be exactly 4 hexadecimal digits, must lie at or above A000, and must be a multiple of 0080 (2k). (2) The size must be in the range 2-384 kb, and must be a multiple of 2. The reason for the "multiple of 2 (kb)" requirement is that EXTENDER tries to allocate memory in 2k increments, corresponding to the IBM spec that Bios ROM's are sized in multiples of 2kb. However, this is somewhat complicated by the larger 16k resolution of the Chips and Technology memory controllers. Without going into a lengthy technical explanation, let's just say that you'll probably notice that HIGHMEM may not report exactly what you asked for with the options; rather, EXTENDER will structure high memory in a manner that satisfies your intent but which is consistent with physical constraints. Sometimes you'll get less memory than you asked for, and sometimes you may even get a little more. Once you are convinced that EXTENDER is working satisfactorily, you may copy it to your hard disk and modify the CONFIG.SYS and AUTOEXEC.BAT files there accordingly. 4. Using the +F000:32 option with AMI Bios chips ------------------------------------------------ The 64k region starting at paragraph address F000 is the Bios ROM. The default operation of EXTENDER is to copy this ROM to Shadow RAM (RAM at the same location) for faster execution of the ROM Bios routines. As a consequence, this RAM is not available to DOS as high memory. Many of the popular 386 clones use a Bios ROM developed by AMI. The more recent versions of these ROMs devote the first 32k to initialization code that is only used during the boot sequence, and use the second 32k for that portion that must remain available at all times. By the time your PC gets to the point in its boot sequence where it is setting up the device drivers (e.g., when it is installing EXTENDER.SYS), the Bios initialization code is no longer needed. If you have one of these AMI Bios chips, you can capture another 32k of high memory by using a +F000:32 option (see section 4, "Command Line Options for EXTENDER.SYS"). Of course, whenever you press Ctrl-Alt-Del to do a warm boot, the ROM Bios initialization code needs to be executed again! And that could be a problem since you've effectively disabled it with the +F000:32 option! Fortunately, EXTENDER.SYS intercepts all keyboard input and keeps an eye out for Ctrl-Alt-Del. When it sees this warm boot request, it first re-enables the entire 64k Bios ROM so that the initialization code is reactivated before the processor tries to execute it. 5. Using HIGHDISK.SYS --------------------- HIGHDISK.SYS is a device driver that uses bank-switching to gain access to the high memory that lies in the same address space as the Bios ROM and any I/O adapters you have installed. This otherwise unusable space can then be used to hold data. The device driver itself may also be loaded into high memory by using HIGHDRVR.SYS to load HIGHDISK.SYS. I.e., a typical command in CONFIG.SYS to do this would be: DEVICE=HIGHDRVR.SYS HIGHDISK.SYS This creates a default 64k RAM disk with 64 directory entries and sectors of 128 bytes each. (This requires at least 64k of unused and contiguous Bank-Switch memory.) A command line option may be used to change the size of the RAM disk as in: DEVICE=HIGHDRVR.SYS HIGHDISK.SYS 127 This creates a 127k byte RAM disk. Such a RAM disk will be allocated to the EGA/VGA display buffer space between A0000 and BFFFF. (You can't get all 128k of that space because there are two memory control blocks of 16 bytes each in the same area. You may ask for more, but if you do, the RAM disk will use some or all of the C0000-C7FFF space occupied by the EGA/VGA ROM, which will necessarily disable its corresponding Shadow RAM.) Other command line options may be used to change the number of bytes per sector and directory entries, as in: DEVICE=HIGHDRVR.SYS HIGHDISK.SYS 127 256 32 This creates a 127k RAM disk with 256 bytes per sector and 32 root directory entries. 6. Video Display RAM above 640k ------------------------------- In general, the region A0000-BFFFF is the video display buffer area. Various display adapters (MDA, Hercules, CGA, EGA, and VGA) typically use only a subset of this space. EXTENDER automatically senses what kind of video display adapter is installed and reserves that portion of this address space that might POTENTIALLY be used by the adapter. You can determine where these areas are with the HIGHMEM command or with the "?" option on the command line of EXTENDER.SYS. However, you may choose to override EXTENDER's rather conservative defaults with the "+" (or "-") command line option. When EXTENDER detects an EGA or VGA adapter, it automatically reserves the entire 128k display buffer between A0000-BFFFF. Theoretically, neither the EGA or VGA should use the 32k monochrome region (B0000-B7FFF), thus you should be able to recover this memory with a +B000:32 option. And if you don't intend to use graphics, you should be able to recover the 64k graphics region (A0000-AFFFF) with the +A000:64 option. Note, however, that the ROM Bios of a few EGA or VGA adapters will write into one or more of these areas even if they aren't in monochrome or graphics mode. So use these options with caution! If a Hercules adapter is found, EXTENDER reserves the entire 64k range B0000-BFFFF in case Hercules graphics modes are used. Otherwise, you may be able to recover quite a bit of memory with an optoin like +B100:60. Normally, an MDA adapter should use only the 4k range B0000-B0FFF, and clearing the screen with a DOS "CLS" command should erase the screen by writing (only) in this region. However, the standard ROM Bios on some clones assume that the MDA display buffer fills a larger region between B0000-B2FFF or B0000-B3FFF. Similarly, a CGA adapter should use only the 16k range B8000-BBFFF; however some software will write to the second 16k between BC000-BFFFF. Therefore, for MDA and CGA adapters, if any Display Buffer RAM is found at B0000, EXTENDER assumes that the entire 32k range B0000-B7FFF is used. Similarly, if any Display Buffer RAM is found at B8000, EXTENDER assumes that the entire 32k range B8000-BFFFF is used. You may be able to recover some additional memory in one of these two ranges with an appropriate "+" command line option. 7. Video Adapter Bios ROMs -------------------------- MDA and CGA use the standard ROM Bios; they have no ROM of their own. Hercules, EGA, and VGA adapters, however, incorporate their own ROM Bios chip right on the adapter card. EXTENDER successfully recognizes these ROMs, but has to treat VGA in a special manner: The IBM VGA adapter has a 24k ROM installed at C0000-C5FFF, which means that the 8k at C6000-C7FFF should be usable. Although almost all VGA clones have a ROM signature that indicates 24k, many of them use the C6000-C7FFF space for ROM Bios or RAM extensions that provide their "Super VGA" features. In particular, the Video7 and Paradise VGA's incorporate their own RAM from C6000-C7FFF. For this reason, when EXTENDER finds anybody's VGA adapter, it automatically assumes that there is a 32k ROM at C0000-C7FFF. 8. Installing FASTOPEN and MODE into High Memory ------------------------------------------------ The FASTOPEN and MODE programs that comes with DOS are TSR's and as such may be loaded into high memory. Once installed, each requires very little memory, something on the order of 9k or less. However, neither will install unless a LOT of memory is available, like around 50-90k (depending on command line options)! The worst part is that if FASTOPEN fails to install itself successfully, it doesn't issue any error message - it simply doesn't display the normal "FASTOPEN installed" sign-on message. Moral: Let FASTOPEN and MODE be the first TSR's that are installed into High Memory in your AUTOEXEC.BAT file so that they get access to the maximum amount of memory. The second hassle with these two TSR's is that they cannot be removed by using HIGHMARK and HIGHUNDO. Evidently they modify memory other than that tracked by these EXTENDER utilities: the interrupt vector table and that memory allocated to them. 9. Using EXTENDER with Expanded Memory -------------------------------------- Expanded memory always has an associated device driver. If that driver is loaded before EXTENDER.SYS in the CONFIG.SYS file, EXTENDER will recognize the 64k EMM Page Frame of the expanded memory and do the right thing: It will disable the motherboard RAM that falls in the same address space so that it doesn't interfere with the Page Frame. This works fine, of course, but loading the EMM driver first precludes the possibility of loading it into High Memory. To get the EMM driver in to High Memory means that it must be loaded after EXTENDER.SYS, but you must be careful! If a REAL expanded memory board is installed then you won't have any problems. For example, if the EMM driver is loaded first (as described above), EXTENDER will report the 64k EMM Page Frame as "EMM Page Frame". Otherwise, EXTENDER will report it simply as "Adapter RAM". But in either case, the memory space will be not be used by EXTENDER. On the other hand, if you don't have an expanded memory board, but have used a device driver (like EMM386.SYS) that emulates expanded memory using extended memory, then EXTENDER.SYS will not know about the page frame unless the emulator is loaded first. If you would rather load the emulator into High Memory (which requires loading EXTENDER.SYS first), then you must use a "-" command line option of EXTENDER.SYS to reserve a 64k region where the Page Frame will be located. 10. Using HIGHMARK and HIGHUNDO ------------------------------- Sometimes it can be useful to remove one or more TSR's from memory, either because you no longer want to use the features that they provide or perhaps in order to make room for another set of TSR's. In order to be able to remove a group of TSR's from high memory, they must be be marked. To mark them, run HIGHMARK once before you use HIGHTSR to load the TSR's. Then later, simply run HIGHUNDO and the mark and all of its assoicated TSR's will be removed. HIGHMARK may be executed more than once to establish levels of TSR's to be removed. Each execution of HIGHMARK places another mark in memory with a unique mark number. Every TSR loaded by HIGHTSR is automatically associated with the most recent execution of HIGHMARK. You can use HIGHMEM to see the marks, their mark number, and the set of TSR's associated with the mark. Every execution of HIGHUNDO will then remove the set of TSR's associated with the most recent HIGHMARK. --------------------- End of file EXTENDER.DOC ---------------------