The World of Computer Software/World_Of_Computer_Software-02-385-Vol-1of3.iso/s/seemem25.zip/SEEMEM.DOC

Text File | 1992-08-16 | 15KB | 331 lines

                                     SEEMEM.EXE
                                     Version 2.5
                                     August, 1992



          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.

          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

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          memory (Segment 9FFFh on a 640k machine), and also between the
          top of conventional memory and the start of the High Memory Area
          (HMA) if any, or the top of Upper Memory (Segment 0FFFFh).  For
          each MCB SEEMEM displays its segment address (in hex), its size
          (in both Kilobytes and bytes), the segment of its "owner," 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

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          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
          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.

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          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
          the bottom UNLESS the /N ("NO PAUSE") switch is used.  The only
          other 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

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          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 2.5

          Since version 2.0, a number of fixes have been made, support for
          MS-DOS 5.00, DR-DOS 6.00, and 4DOS 4.00 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.

          A switch was 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.  SEEMEM now automatically detects
          redirection and turns off pausing when the output is redirected
          to anything but the standard output (normally the screen).
          Nevertheless, the /P switch remains just in case you want it.

          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"), and if in
          upper memory says "LoadHi" also.  In addition DR-DOS 6.00
          provides more detail of the loader of TSR's so, in addition,
          under DR-DOS version 6.00 a UMB TSR may say either "LoadHi" if
          the LoadHigh or DeviceHigh or HighInstall loaded it, or "AutoHi"
          if it loaded itself in an UMB without help.  4DOS is an example
          of a program which can do that, and there are a number of others.

          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.

          Enjoy,

                 Rick Housh










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