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Text File | 1993-01-17 | 14.9 KB | 307 lines

SEEMEM.EXE Version 2.65 January, 1993 Author: Tedrick A. Housh, Jr. 5811 West 85th Terrace Overland Park, KS 66207 Electronic Mail: CompuServe 72466,212 Genie R.HOUSH The objective of SEEMEM is to display information about the current use of MS-DOS memory by the operating system, and resident processes and data. It is designed to make full use of the new memory facilities provided by DOS version 5.0, and to provide information similar to that provided by the DOS utility MEM. However, it provides this information even when DOS does not control Upper or Extended memory, and even when HIMEM.SYS and EMM386.EXE are not loaded, and recognizes UMB's created by other programs, such as Quarterdeck Software's QEMM386 (for 386 and higher) and QRAM (for 286 cpu's with EMS version 4.00 hardware or Chips and Technologies Shadow Ram). It works with these programs on all versions of DOS greater than 1, and on all CPU chips, 8088 and higher, although the memory detail displayed increases with increase in CPU version. As of SeeMem version 2.00, it provides full support for DR-DOS 6.00 also, and with version 2.65 for Qualitas' 386Max, and Helix Software's NetRoom. SEEMEM was written in Turbo Pascal 6.00, as an exercise in the use of the Built-In Assembler (BASM). In that connection, all necessary DOS functions were specifically coded in BASM, as were all functions which necessarily interface with the extended memory (XMS) driver provided by HIMEM.SYS, or its counterparts such as QEMM386.SYS, or QEXT.SYS, or EMM386.SYS. This completely eliminates the need for the Turbo Pascal DOS unit, or a unit to interface with the XMS and UMB device drivers. All the low level functions necessary for this purpose are included directly in the SEEMEM.PAS file as BASM code, and the .PAS file is independent and completely self-supporting. The display output for SEEMEM is in three parts. The first part, which may include several screen pages, displays every memory control block (MCB) between Segment 0 and the top of conventional memory (Segment 9FFFh on a 640k machine), and also between the top of conventional memory and the start of the High Memory Area 1 (HMA) if any, or the top of Upper Memory (Segment 0FFFFh). For each MCB SEEMEM displays its segment address (in hex), its size (in bytes), the segment of its "owner," its "parent" (i.e. the MCB of the program that loaded it), its type (e.g. TSR or Environment), and its name (if determinable). The second part is a display of EMS (Expanded Memory) if applicable. This displays the version number of the EMS device driver, the page frame segment, the total size of the installed EMS memory, the number of mapping register sets available, whether or not nonvolatile handles (will survive warm boot) are available, the number of DMA channels , the maximum number of EMS handles supported, the number of free handles, free pages, page size, and free memory, and for each handle in use, the handle number, the number of EMS pages, the page size, the memory used, and if available, the handle name. This second part may occupy more than one screen page. The third part displays XMS information (if a driver is installed), including XMS version number, revision number, the XMM Control Vector in segment:offset form, total XMS free memory, and largest free XMS block. With respect to the High Memory Area (HMA) SEEMEM shows whether the A20 line is currently enabled, whether HMA is implemented, whether the HMA is available for use. If the DOS version is 5.00 or greater SEEMEM also will say whether DOS is resident in the HMA (DOS=HIGH in config.sys), and, if so, how much of the HMA DOS has left available for additional buffers, etc. SEEMEM also displays the location of DOS when it is located elsewhere (i.e. ROM or Conventional memory). The third part also displays information about Upper Memory Blocks (UMB's) if available: whether UMB's are implemented, whether they are controlled by device driver or by DOS itself (with DOS 5.00 and higher), whether UMB's are linked to conventional memory (DOS 5.00) or are independent, and whether UMB's are implemented by DOS=UMB in CONFIG.SYS (DOS 5.00). Seemem does NOT display device driver information loaded under DOS version 4.xx or higher's "secondary" MCB's, although it will display such primary MCB's other software may use to load such device driver's "high" in UMB's if each is given its own MCB. This was a design decision to avoid "clutter." Plenty of programs are available to "walk" the device chain and display this information. A word about resident code names is in order. Under DOS 2.xx the name of resident loading programs is not determinable. With DOS 3.xx the name may be determined from the environment, unless that was released back to DOS's pool on installation. With DOS 4.xx and higher an eight character name is inserted in the last eight bytes of the 16 byte MCB, and therefore is always available. Some other programs which control UMB's insert the eight character name in the MCB under any DOS version, but this is not used by SEEMEM. SEEMEM uses the most detailed information available through DOS. Therefore, if the DOS version is 4 or higher, and 2 the environment pertaining to the process is still resident, the program name and extension is taken from the environment (although the drive and directory information is stripped from the filename before display). A full explanation of the XMS, UMB, and HMA standards is not within the scope of this documentation, however an understanding of a few of the more obscure facts will help understand SEEMEM's operation. The "XMS Specification" for extended memory is similar to the EMS spec for expanded memory. It provides functions for implementing use of extended memory with handles in a manner very much the same as EMS does for expanded memory. The High Memory Area (HMA) is the 64 kilobyte (less 16 bytes) just above the 1 megabyte limit of the 8086 and 8088 chips. Obviously, then XMS extended memory and the HMA require a 80286 chip or higher. However, through a clever addressing scheme, and an additional hardware address line, an 80286 or higher can address the HMA in "real" mode, i.e. as "non-extended" memory. Although XMS drivers existed before DOS 5.00, and some alternative DOS-like operating systems allowed the use of this space for some things, DOS 5.00 now allows DOS itself to be loaded there, substantially increasing the possible useable memory space in lower memory previously used by DOS. Although the protocols and specifications for Upper Memory Blocks (UMB's) are contained in the original XMS specifications, they are NOT necessarily part of the XMS driver itself, and in fact were not implemented by the first MicroSoft driver, HIMEM.SYS. The XMS specification only provides one control vector however, so if all UMB calls need be implemented through that vector, a UMB driver must be integrated with the XMS driver, or must hook that vector (necessarily implying that it must be loaded after the XMS driver has installed the vector) unless it is completely integrated. However DOS 5.00 has supplied interrupt 21h function calls to manipulate the use of existing UMB's for detecting the existence, state and governing the rules of use of UMB's, and these function calls are not dependent on the existence of any device driver, nor for that matter, the existence of any extended memory, or a chip higher than that 8088-8086. The thought may take some getting used to, but this means that UMB's can exist without any driver or control vector at all. In fact there is at least one program available which acts as though it were a device driver, creates UMB's from the shadow ram available through some motherboard chipset implementations, hands it over to DOS, and then just aborts, itself disappearing from memory. DOS then owns, and makes available some UMB's with no device driver to control them. SEEMEM can also detect this type of UMB and display its state. DOS 5.00 provides greatly increased support for XMS, HMA, and UMB's, and SEEMEM uses all of it, where it is possible to do so. In order that it may support full display redirection SEEMEM does not do any direct video memory-mapped display. All display is through DOS or BIOS. Each screen is paged with a "MORE" line at 3 the bottom UNLESS the /N ("NO PAUSE") switch is used. Another switch available is the help /H or /? switch, which displays a simple help message. The output may be directed to a file or a device such as a printer, in which case you will probably wish to bypass paging also, with the /n switch. As of SeeMem version 2.00 SeeMem detects this redirection and turns paging off by itself. For example SEEMEM /N > PRN would send the output of the program to the printer for a permanent record. In order to speed the output slightly the DOS IOCTL function is used to switch to "raw" output mode, and is returned to its prior state, probably "cooked," upon program termination. This speeds up output by eliminating checks for ^S, ^Q, ^C and expansion of tabs, etc., so you cannot manually pause the program or "break" it. No tabs or other characters requiring interpretation are used however, so you should see no difference due to disallowance of "cooked" mode. If you insist on a "scrollable" output I have successfully used the J.P. Software's 4DOS command shell internal LIST command with SEEMEM to provide this with the following command line: SEEMEM /N | LIST /S This provides an output which uses LIST to scroll from top to bottom. I have made the source code available in Turbo Pascal 6.0 on the Borland Support area on GEnie and in the Borland Programming Area on CompuServe. The program is copyright but donated to the public domain without any restriction, except that it be distributed in its original form with appropriate authorship credit, with no charge other than reasonable fees for duplication and distribution, including by electronic means. It is specifically intended and permission is granted for distribution by commercial electronic sources for their regular and customary access and membership fees even though they may be operated for profit. No warranties of any kind accompany SEEMEM, and the author assumes no responsibility for any consequences of its use, either direct or consequential. The basic idea for SEEMEM is not new, of course and all parts of it borrow heavily upon prior, similar programs. Perhaps it should be named YAMEM (Yet Another MEMory display program). Nevertheless it does do some things no other does (that I know of) and it is a demonstration of Turbo Pascal 6's BASM facility which clearly shows the practicality of the TP environment for low level system programming. In fact, I don't think the same thing could be done in C with faster or smaller code resulting. Yeah, I know, TP is primarily a shell for the assembly stuff, but at least it can do that now, and very adroitly, too. New in Version 2.65 4 Since version 2.0, a number of fixes have been made, support for MS-DOS 5.00, DR-DOS 6.00, and 4DOS 4.xx has been expanded considerably. In addition adjustments have been made for Windows 3.10 enhanced mode. Most of the fixes were necessary because arithmetic has never been my forte' and calculations of block sizes, etc. were not quite accurate enough. Most user's apparently didn't notice but a few did call my attention to this, for which I thank them. Two switches were added, /L for "Long" which sets the page length in each section of the report to 55 lines so that redirection to the printer will look better, and /C which allows displays of control and "high order" characters which are ordinarily automatically converted to something any printer can handle. SEEMEM now automatically detects redirection and turns off pausing when the output is redirected to anything but the standard output (normally the screen). The owner names were changed somewhat. Most are self explanatory to those who need the information. "TSR" represents a resident program (if it's resident it's really a "process"). Support has been added for Quarterdeck's QEMM and QRAM, Qualitas' 386Max, and Helix's NetRoom. Varying degrees of detail are gleaned from these memory managers. Staying as generic as possible requires some compromises. There were a number of other technical changes since version 2.00 which are mentioned in SEEMEM's history file SEEMEM.HST, which accompanies this documentation. Source code (Turbo Pascal 6.0) is available by sending a blank, formatted disk and appropriately sized SASE to the above address, or may be downloaded from the Borland Turbo Pascal Forum on CompuServe Information Service (search for keyword SEEMEM265). Enjoy, Rick Housh 5