Cream of the Crop 3/Cream of the Crop 3.iso/diag/see270.zip/SEEMEM.DOC

Text File | 1994-02-23 | 15KB | 294 lines

                                   SEEMEM.EXE
                                  Version 2.70
                                 February, 1994



        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 6.20, 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 7.00, 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

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        (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


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        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.

        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

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        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 7.0 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'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.


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                               New in Version 2.70

        Since version 2.6, a number of fixes have been made, support for
        MS-DOS 6.xx, DR-DOS 6.00, and 4DOS 5.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 7.0) 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 SEEMEM270).

        Enjoy,

               Rick Housh















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