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Dynamic-Virtual Memory Allocation Manager (tm) DVMAM (tm) Version 1.10 Copyright 1990 R.C.B. Enterprises Turbo C version October 8th, 1990 Table of contents ----------------- Page What is Shareware.......................................... 1 Disclaimer of warranty..................................... 1,2 Trademarks................................................. 2 What should I have received with DVMAM?.................... 2 So then, what is DVMAM?.................................... 2 How does DVMAM function?................................... 3 So what are the memory limits?............................. 3,4 Important considerations for memory allocation............. 4,5 A. Extended memory....................................... 4 B. Expanded memory....................................... 5 What are the functions that I can use in my system?........ 5-9 A. Extended memory functions............................. 5,6 I. alloc_ext........................................ 5 II. dealloc_ext...................................... 5 III. save_ext......................................... 5 IV. load_ext......................................... 5,6 V. kbytes_ext....................................... 6 VI. ext_free......................................... 6 VII. cpu_type......................................... 6 VIII. ext_setup........................................ 6 B. Expanded memory functions............................. 6,7 I. alloc_ems........................................ 6 II. dealloc_ems...................................... 6 III. save_ems......................................... 7 IV. load_ems......................................... 7 V. pages_ems........................................ 7 VI. ems_installed.................................... 7 C. DVMAM controller functions............................ 7-9 I. alloc_mem........................................ 7 II. dealloc_mem...................................... 7,8 III. save_memory...................................... 8 IV. load_memory...................................... 8 V. bytes_available.................................. 8 VI. bytes_total...................................... 8 VII. set_memory_usage................................. 8,9 VIII. memory_setup..................................... 9 IX. memory_shutdown.................................. 9 How do I link the DVMAM library into my program?........... 9,10 A. TURBO C projects...................................... 9 B. TURBO C command-line compiler......................... 9,10 C. TLINK................................................. 10 Thanks..................................................... 11 Version 1.10 release....................................... 11 Registration form.......................................... 12 (unlabeled) I What is Shareware? ------------------ Shareware distribution gives users a chance to try software before purchasing it. If you try a Shareware program and continue using it, you are expected to register that program. Individual programs differ on the details. Some programs request registration while others require it and others allow an optional maximum trial period that the program may be freely used before registration is required. With the registration you may receive only the right to continue to use that product to a full blown version of the program with printed manual and source code. Copyright laws apply both to Shareware and commercial software and the copyright holder retains all rights with a few specific exceptions stated below. Shareware authors are accomplished programmers just like commercial authors and the programs are of comparable quality. (In both cases there are good programs and bad programs.) The main difference is in the method of distribution. The author specifically grants the right to copy and distribute the software either to all or a specific group. For example, some authors require written permission before a commercial disk vendor may copy their software. Shareware is a distribution method, not a type of software. You should find software that suits your needs and pocketbook whether it's commercial or Shareware. The Shareware system makes fitting your needs easier because you can try the software before you purchase the software. And because the overhead of producing the program is low, prices are also low (in most cases). Shareware has the ultimate money-back guarantee.. If you don't use the product, don't pay for it. Disclaimer of Warranty ---------------------- The DVMAM program and manual are sold "as is" and without warranties as to performance of merchantability or any other warranties whether expressed or implied. Because of the various hardware and software environments into which the program may be put, no warranty of fitness for a particular purpose is offered. The user must assume the entire risk of using the program. Any liability of the seller will be limited exclusively to product replacement or refund of purchase price. R.C.B. Enterprises assumes no liability for damages, direct or consequential, which may result from the use of DVMAM. DVMAM is a Shareware program and is provided at no charge to the user for evaluation. Feel free to share it with your friends provided it is not altered or as part of another system. If you find DVMAM useful and continue to use DVMAM after a 30 day trial period, a registration payment of $35 is required. The $35 registration fee will license one copy for use on any one computer at a time. Anyone distributing DVMAM for any kind of remuneration must first contact R.C.B. Enterprises for authorization. Page 1 You are encouraged to pass a copy of DVMAM along to your friends for evaluation. Please encourage them to register their copy if they find that they can use it. All registered users will receive the latest copy of DVMAM in all memory models supported by the requested compiler version, the ability to access all available memory (if you're a Turbo Pascal user), and a bound printed manual. Compilers currently supported as of this release are Turbo Pascal 4.0 thru 5.5, Turbo C 2.0 and Microsoft C 5.0 and higher. The registration fee of $35 is the same for all versions of DVMAM. The source (Assembler and C for TURBO C and Microsoft C, Assembler and Pascal for TURBO PASCAL) is available with DVMAM for $50 (this includes the source and the latest release of DVMAM). Please remember to specify compiler when you register. Trademarks ---------- Before we continue, we need to cover trademarks so the appropriate companies receive credit. Microsoft is a registered trademark of Microsoft corporation IBM is a trademark of International Business Machines TURBO Pascal and TURBO C are trademarks of Borland International Dynamic-Virtual Memory Allocation Manager and DVMAM are trademarks of R.C.B. Enterprises LIM is a trademark of Lotus-Intel-Microsoft corporations What should I have received with DVMAM? --------------------------------------- With the Shareware version of DVMAM you should have received the following files: DVMAM.DOC - This is this file DVMAMSTC.LIB - Library containing the small model for Turbo C DVMAM.H - Turbo C include file DV_TEST.C - A test program that shows memory allocation in action DV_REG.TXT - A simple registration form for DVMAM. This form is also found at the end of this document. DV_BUG.TXT - A bug report form for DVMAM - hopefully this will never be used. DV_PRINT.BAT - A small batch file that prints this file. README.1ST - A small file describing DV_PRINT and also contains a list of these files. So then, what is DVMAM? ----------------------- The Dynamic-Virtual Memory Allocation Manager uses conventional, extended and expanded memory in your computer to allow your programs to access up to 24 megabytes of memory. This memory, which on most systems is used only for RAM disks or print spoolers, can now be used effectively for any application as though it was conventional memory by using the DVMAM system. Page 2 How does DVMAM function? ------------------------ DVMAM uses a main set of generalized functions to control specific functions focused at specific memory types. DVMAM is capable of allocating memory to a specific memory type or over all memory available in the system your program is being executed in. Once memory has been allocated (reserved for future use), its information is stored in memory to be used by DVMAM in the future and a block identification number is returned to the user. This number must be saved in order to use the memory just allocated. The maximum amount of space that can be allocated to one block is 64k bytes (or 65536 bytes). In order to use this memory a data transfer area is established by DVMAM to operate as a medium between the normal C functions and DVMAM. dvmam_dta is declared as a far pointer by DVMAM and serves as this transfer area. A specific amount of memory is reserved for dvmam_dta when DVMAM is initialized with a function called "memory_setup". The amount of memory reserved for dvmam_dta is specified by the user and should be no larger than the largest block you intend to allocate. If it is larger, precious bytes will be reserved and never used. As with the largest possible block size being 64k, the largest size of dvmam_dta is also 64k. Once dvmam_dta has been set, the contents stored in the memory location used by dvmam_dta may be saved with a function called "save_memory". The block identification number is passed to the function and the appropriate memory type, size and location is determined. The contents of dvmam_dta is then transferred into that location. Similar to the function above that saves information, "load_memory" will load data in from a specific memory location into dvmam_dta. NOTE: DVMAM does not check to see if the contents of DVMAM have been changed and not saved. Once a call to "load_memory" has been made the data in dvmam_dta will be destroyed as new data replaces it. So what are the memory limits? ------------------------------ Each memory type has specific limits. Conventional memory is available on all machines. The amount of memory that may be used is dependent on the size of the programs loaded into memory. So naturally a program occupying 128k of memory will leave more available than a program occupying 384k of memory. The limit on conventional memory is 640k and all programs executed will take up some or all of conventional memory. With new innovations in computing, more and more specialized drivers and TSR (Terminate-Stay Resident) programs are storing the majority of their information in extended memory and freeing more conventional memory to be used by larger, more memory intensive programs. This is important in many cases because the majority of programs currently do not support either extended or expanded memory. LIM EMS (expanded memory) supports up to 8 megabytes of memory. This Page 3 memory is governed throughout the system by a driver known as an EMM driver (Expanded Memory Manager). The EMM keeps track of memory that has been allocated and that which hasn't. Since the EMM uses a separate external driver, other programs are able to allocate expanded memory and not interfere with each other. DVMAM, before attempting to allocate expanded memory, first checks to see if the EMM has been installed. If an EMM has not been installed, DVMAM will make no attempt to allocate expanded memory. This is done at run-time, not during link time, so a program that supports expanded memory will make use of it when it is available. DVMAM requires an EMM that supports the LIM EMS standard version 3.2 or higher. Extended memory is memory directly supported by the microprocessor and supports up to 16 more megabytes of memory. Only 80286 machines and their successors (such as the 80386 and 80486) support extended memory. Machines such as 8086 and 8088 do not support extended memory. DVMAM, before attempting to allocate extended memory, first checks the microprocessor type. If a '286 or higher is not in use, DVMAM will make no attempt to allocate extended memory. This action, as with checking for the EMM, is done at run-type and not link time. A program that supports extended memory will only make use of it when it is available. Important considerations for memory allocation ---------------------------------------------- Extended memory --------------- There is no way to tell if another program is using extended memory so its usage should be optional unless it is run in a single program environment. In other words, if extended memory is available and it is known that no other programs are making use of extended memory, it is entirely safe to use. However, if other programs (such as RAM disks, print spoolers or disk cache programs) are running in the system along with the main application, data allocated to your program will more than likely destroy data in extended memory being used by those sorts of programs. So making extended memory optional is advised. If you are considering an interrupt intensive program (such as networking, communications or other programs that make heavy use of interrupts or are dependant on interrupts), extended memory should be avoided. Each time data is moved to or from extended memory, interrupt processing is halted. A few examples of the effects of extensive extended memory moves are: 1. If characters are coming in through your serial port, or through a network interface, during an extended memory move those characters will be lost. 2. Characters typed at the keyboard may be skipped during a move. 3. If usage is extensive enough, one or more seconds may be lost by the system clock. Page 4 Expanded memory (EMS) --------------------- If expanded memory is in use it must be noted that the EMM will allocate 16k chunks. It is important to consider this when allocating expanded memory. If only 4k is needed and 256k of expanded memory is available, under normal circumstances it would be appropriate to assume that 64 blocks of memory could be allocated. Since 16k blocks are allocated at a time, only 16 blocks would be used and 12k of memory per block would be wasted. Expanded memory is also different from the other types of memory in that it uses a separate, external driver to control the expanded memory. Memory allocated to the EMM is kept allocated and assumed it is still in use by your program long after your program may have finished executing. This makes it unavailable for use by other programs in the future that may make use of expanded memory. It is then extremely important to deallocate all expanded memory before terminating your program. What are the functions that I can use in my system? --------------------------------------------------- Extended memory functions ------------------------- The extended memory functions control all extended memory available in the system. Function name: alloc_ext Prototype: int alloc_ext(int size); Use: alloc_ext attempts to allocate memory of <size> bytes. alloc_ext returns the handle of the memory allocated or -1 if the attempt to allocate memory failed. Function name: dealloc_ext Prototype: int dealloc_ext(int handle); Use: dealloc_ext frees the memory specified by the block identifier. Be deallocating memory, it is once again made available and can be allocated again later in the program. dealloc_ext returns 0 on success, -1 on failure. Function name: save_ext Prototype: int save_ext(int handle, void far * buffer); Use: save_ext moves data from the location specified by buffer into the memory location specified by handle. save_ext returns 0 on success, -1 on failure. Function name: load_ext Prototype: int load_ext(int handle, void far * buffer); Page 5 Use: load_ext moves data from the memory location specified by handle into the location at buffer. load_ext returns 0 on success, -1 on failure. Function name: kbytes_ext Prototype: int kbytes_ext(void); Use: kbytes_ext returns the total amount of memory (in kbytes) available as extended memory. Function name: ext_free Prototype: long ext_free(void); Use: ext_free returns the amount of extended memory in bytes available to be allocated. Function name: cpu_type Prototype: int cpu_type(void); Use: cpu_type returns the type of microprocessor available on the system DVMAM is currently being used on. Possible return types are: 86 for 8086 and 8088 systems, 186 for 80186, 286 for 80286 and 386 for 80386 systems. Function name: ext_setup Prototype: void ext_setup(void); Use: ext_setup prepares all structures and data used by DVMAM for extended memory allocation. Expanded memory functions ------------------------- The expanded memory functions control all expanded memory available in the system. Function name: alloc_ems Prototype: int alloc_ems(int size); Use: alloc_ems attempts to allocate expanded memory via the EMM. alloc_ems returns the handle to expanded memory, -1 the attempt to allocate memory failed. Function name: dealloc_ems Prototype: int dealloc_ems(int handle); Use: dealloc_ems frees the memory specified by handle via the EMM. This memory is then made available for use later in program execution or by other programs which may use expanded memory. dealloc_ems returns a 0 if the memory has been successfully deallocated, -1 if the function failed. Page 6 Function name: save_ems Prototype: int save_ems(int handle, void far * buffer, unsigned int size); Use: save_ems moves data from the memory location specified by buffer into the expanded memory location specified by handle. save_ems returns 0 upon a successful memory move, -1 if the attempt to move data failed. Function name: load_ems Prototype: int load_ems(int handle, void far * buffer, unsigned int size); Use: load_ems moves data from the memory location specified by handle into buffer. load_ems returns 0 upon a successful memory move, -1 if the attempt to move data failed. Function name: pages_ems Prototype: int pages_ems(int mode); Use: pages_ems returns either the total number of pages in expanded memory or the number of pages available to be allocated. Each page is 16k bytes long. The number of pages returned by pages_ems is determined by mode. A value of 0 will return pages available and a value of 1 will return the total number of pages in expanded memory. pages_ems will return -1 if the function failed. Function name: ems_installed Prototype: int emm_installed(void); Use: emm_installed checks to see if the EMM has been installed in memory. If the EMM has been located a value of 1 will be returned, otherwise a value of 0 is returned. DVMAM controller functions -------------------------- These are the main functions used by DVMAM. DVMAM keeps track of all the information required for use of the above functions. This information includes handles, sizes and pointers. This makes allocation easier on the programmer because all use of extended, expanded and conventional memory is done by DVMAM. Function name: alloc_mem Prototype: int alloc_mem(int size); Use: alloc_mem checks for memory available and attempts to allocate to that memory. If the allocation is successful, a block identification number is returned, otherwise -1 will be returned to alloc_mem. Function name: dealloc_mem Prototype: int dealloc_mem(int block); Page 7 Use: dealloc_mem attempts to deallocate memory allocated with alloc_mem. This will make it available for use elsewhere in your program. dealloc_mem returns 0 upon successful deallocation, -1 if the deallocation attempt failed. Function name: save_memory Prototype: int save_memory(int block); Use: save_memory moves the data located in dvmam_dta into the memory location and type specified by the block identification number returned by alloc_mem. save_memory returns 0 if the attempted move was successful, -1 if the attempted move failed. Function name: load_memory Prototype: int load_memory(int block); Use: load_memory moves data from the memory location and type specified by the block identification number into dvmam_dta. load_memory returns 0 if the attempted move was successful, -1 if the attempted move failed. Function name: bytes_available Prototype: unsigned long bytes_available(void); Use: bytes_available checks all memory types in use and returns the total amount of memory available to be allocated by alloc_mem. Function name: bytes_total Prototype: unsigned long bytes_total(void); Use: bytes_total checks all memory types in use and returns the total amount of memory in those memory types. This is total system memory and is not the amount of memory that can be used. Function name: set_memory_usage Prototype: void set_memory_usage(int usage); Use: set_memory_usage informs DVMAM of which types of memory you wish to attempt to use. By default DVMAM will attempt to use conventional, expanded and extended memory. There are four nyms associated with values that may be used to determine which memory types to use: NONE = 0 USE_CONV = 1 USE_EXT = 2 USE_EMS = 4 Examples: set_memory_usage(USE_CONV); set_memory_usage(USE_EMS+USE_EXT); Page 8 Examples continued.. set_memory_usage(USE_EXT+USE_CONV); set_memory_usage(NONE); Function name: memory_setup Prototype: void memory_setup(unsigned int size); Use: memory_setup prepares extended memory structures, DVMAM structures and allocates memory to dvmam_dta. The amount to memory allocated to dvmam_dta is specified by size. Function name: memory_shutdown Prototype: void memory_shutdown(void); Use: memory_shutdown frees all memory in use by DVMAM including dvmam_dta, extended, expanded and other conventional memory. How do I link the DVMAM library into my program? ------------------------------------------------ TURBO C Projects ---------------- TURBO C projects take out a majority of the worry about linking the DVMAM library into your program if you prefer to use the integrated environment. To create a project for TURBO C, simply make a text file with the files: DVMAMSTC.LIB MYFILE.C MYFILE.C is the filename of your program. In many cases there will be more files that make up the entire program than just the one specified by MYFILE.C. These files also need to be added to the project list. Once the project file has been created the TURBO C environment needs to know which project it is going to use to create the desired program. Typing ALT-P to go to the project menu and entering the project name will do this. TURBO C command-line compiler ----------------------------- If the environment is not used there are two other methods that may be used to link the DVMAM library into your program. The first is by adding the name DVMAMSTC.LIB to the list of command-line options with the TCC command-line compiler. The second is using TLINK which should have come with your TURBO C compiler. Page 9 Using TCC is definitely the easier of the two methods as the default libraries normally used with TURBO C are automatically included when TCC attempts to link your file. This is a typical example of using TCC to compile and link DVMAMSTC.LIB into your program C:>TCC MYFILE.C DVMAMSTC.LIB This simple example will compile MYFILE.C and attempt to link the files MYFILE.OBJ (which is created by TCC) and DVMAMSTC.LIB with the libraries that are normally used by TURBO C. It is important to make sure that the memory model being used in MYFILE.C is the same as is used in DVMAMSTC.LIB. The filename DVMAMSTC.LIB may be broken down as follows: DVMAM S TC.LIB. The DVMAM naturally standing for DVMAM. S indicates small memory model. For other memory models, C (compact), M (medium), L (large) and H (huge) will be used. TC stands for TURBO C and the LIB indicates a library file. TLINK ----- Attempting to link your program together by directly invoking TLINK is definitely more difficult as ALL libraries must explicitly be specified. A simplified example of using TLINK would be as follows: TLINK MYFILE,MEMORY,,DVMAMSTC TLINK will then attempt to link DVMAMSTC.LIB into the file MYFILE.OBJ and create MEMORY.EXE. This would only work if no other functions other than those in DVMAM which are written explicitly in assembler were to be used (expanded and extended memory). Since DVMAM has been written both in assembly and TURBO C many of the functions used in DVMAM use functions from the standard TURBO C library. Those libraries may be specified on the command line and linked in. A more complicated example would be: TLINK MYFILE C0S,MEMORY,,DVMAMSTC EMU CS MATHS TLINK would then attempt to link MYFILE.OBJ, C0S.OBJ, DVMAMSTC.LIB, EMU.LIB, CS.LIB and MATHS.LIB together into an executable file called MEMORY.EXE. It is critical that the file MYFILE is compiled and linked in the same memory model as the libraries you intend to use. In the above example CS.LIB, MATHS.LIB, DVMAMSTC.LIB and C0S.OBJ are all libraries that use the small memory model. Page 10 Thanks ------ Thank you for your interest in the Dynamic-Virtual Memory Allocation Manager. We'd love to hear from you with your comments on DVMAM and any suggestions you may have as to how to improve DVMAM. We realize that programs may float around for many months before they fall into your hands. Feel free to write at any time for information about other products by R.C.B. Enterprises or for information about what is happening in the development of a specific program. If you discover that the version of DVMAM you are using has been upgraded since you received your demo version you may request a demo be sent out to you for a $3 charge to cover copying and postage. Our address is: R.C.B. Enterprises, Team A 15 Central Way, #287 Kirkland, WA. 98033 Version 1.10 release -------------------- Version 1.10 is virtually the same as version 1.00. It contains one bug fix performs two more checks than the previous version. The bug was in the deallocation of memory. Blocks deallocated were deallocated, but not marked as so. So, depending on how much memory you have in your machine, you would be able to allocate memory only a certain number of times before you were unable to allocate. In the case of the main testing computer with 2.2 megs, we were able to allocate 76 blocks before all blocks were used. This bug is non-destructive and should not effect users of version 1.0. There are two more checks performed. One is that you cannot allocate more memory to a block than is allocated to dvmam_dta. So if you allocated 16k to dvmam_dta, you could not allocate a block that was 32k. The other check is on the boundaries in extended memory. It now floats instead of staying in a stable position. This simply improves performance of the extended memory engine. Page 11 Dynamic-Virtual Memory Allocation Manager 1.10 Registration Form Thank you for taking the time to register DVMAM Company name: _________________________________________ User name: _________________________________________ Address: _________________________________________ _________________________________________ City,State,Zip: _________________________________________ Phone: (______) ______-_________ (in case there are questions about your order) Date of registration: ___________ Compiler: TURBO C [ ] TURBO PASCAL [ ] Microsoft C [ ] Compiler version: ______________ I would like information about other products [ ] ========================================================================== Number of copies desired at $35 (U.S. currency) per copy _______ $5 for shipping $ 5.00 (Washington residents add 8.1% sales tax) $ _______ Total amount enclosed $ _______ Payment type: ____ Money order/Cashiers check ____ VISA ____ Personal/Business check ____ Master Card Please make checks payable to R.C.B. Enterprises. Personal and business checks please allow at least 10 business days to clear. Card number: ________________________ Signature: ________________________ Expiration date: __________________ Please send a copy of this registration form with registration payment to: R.C.B. Enterprises, Team A 15 Central Way, #287 Kirkland, WA. 98033