QEMM
Encyclopedia
Quarterdeck Expanded Memory Manager (QEMM, icon, though not by those who developed it), was a memory manager
produced by Quarterdeck Office Systems
in the late 1980s through late 1990s. It was the most popular memory manager for the MS-DOS
and other DOS
operating system
s.
chipset
s. 2.02 added SHADOWRAM switch. QEXT now correctly reallocates XMS. It includes VIDRAM, Optimize, LOADHI from QEMM 6.02, Manifest 1.13.
QEMM Game Edition: It is a version of QEMM that includes Quarterdeck GameRunner. Patches for regular QEMM do not work on QEMM Game Edition.
QEMM MegaBundle: In the version shipped with SideKick for Windows, it is a version with SideBar 1.00 (1994-08-22) and QEMM 7.5.
DESQview 386: It includes DESQview
and QEMM-386.
, and HeadRoom/NetRoom.
Compaq
DOS 3.31, released in November 1987, was the first DOS operating system
to bundle technology similar to QEMM-386, incorporating a 386-mode EMS manager called CEMM
. QEMM was the first V86 memory manager on the market.
(UMA), expanded memory
(EMS) and extended memory
(XMS), Virtual Control Program Interface
and DOS Protected Mode Interface
.
MagnaRAM was also released as a separate utility.
MagnaRAM worked by replacing a portion of Windows' virtual memory
system. MagnaRAM would insert itself in the string of Windows Programs that determined what pieces of RAM will be moved to the hard disk. Instead of writing directly to the hard disk, the information to be written would go to MagnaRAM's own buffer as this was a faster process. During CPU idle, MagnaRAM would compress the information in its own RAM buffer. When the RAM buffer becomes full, it is then swapped to the hard disk taking both less time and less space.
It is shipped with QEMM and DESQView.
Version 4.03 supports IBM Memory Expansion Option boards with 2-8MB memory.
Beginning with QEMM version 8, it allows ROM contents in UMA to be relocated to provide more memory for TSRs. Additional Stealth Windows compatibility is provided with VxDs.
VIDRAMEMS supports DMA-based video memory access at the expense of EMS memory for buffer.
By default, QEMM 8.0 only provides total up to 64MB XMS, EMS and VCPI memory, unless USERAM= parameter is used.
QEMM only provides total up to 256MB XMS, EMS and VCPI memory.
Batch file line limit is 512 for QEMM versions up to 6.02.
New QEMM parameters include DISKBUFFRAME=xx (DBF), EXCLUDESTEALTHINT=xx (XSTI), SHADOWRAM=xxx (SH), UNMAPFREEPAGES=Y/N (UFP), WINSHRINKUMBS=N (WSU)
By default, EMS is unmapped when Stealth is active.
Optimize can support batch file up to 20KB.
The 64MB limit was removed from EMBMEM (EMB) parameter.
TESTBIOS's 'Dan and Larry' messages were removed.
Manifest was updated to 1.13.
Vidram now support systems with over 640KB conventional memory under DOS 5 and had not allocated UMBs.
Vidram later than 6.04 uses EMS by default.
New features include DOS-Up, Stealth ROM, Stealth DoubleSpace.
New utilities include SWAPECHO.COM, OPTIMIZE.EXE (replaced OPTIMIZE.COM), QDPMI (Quarterdeck DPMI 0.9 host), QSETUP (QEMM Setup for Windows), SCANMEM.COM (USERAM= memory scanner).
Updated utilities include Manifest 2.0.
Addd support of Virtual Mode Extensions and Page Size Extensions found in Pentium, later Intel 80486, or later CPUs; Bus-Mastering hard drives.
Optimize supports disk compression software, DOS 6 multi-config, AUTOEXEC.BAT IF statements.
Vidram can now operate in Windows Enhanced mode DOS windows.
QEMM 7.0x loads itself to shadow RAM by default.
New Optimize switches include /NOFLUSH (/NOFL).
Stealth DoubleSpace virtualizes DOS Function 9.
DOSDATA improves compatibility with Stacker 3.1, supports PC-DOS 6.1 and XTRADRIVE or OS/2 2.x Boot Manager.
Stealth Windows driver was updated to 7.02.
QEMM driver now supports Compaq 20/e and 25/e.
included a built-in EMM which offered EMS to DOS windows during Windows sessions only. These versions could not yet create Upper Memory Blocks. Digital Research
's DR-DOS
5.0 (1990) was the first non-vendor-specific DOS to offer the UMB technology, incorporating a 386-mode XMS/EMS manager also called EMM386
. It could also allocate some of the video memory or EMS memory as UMB memory. MS-DOS finally offered UMBs in 1991 with version 5.0. MS-DOS's EMM386 required HIMEM to be loaded first, while DR-DOS's EMM386 fulfilled both roles and did not need a separate XMS driver, which was still provided but only needed on 80286-based machines (originally named HIDOS.SYS, later HIMEM.SYS). If an XMS driver was loaded before DR-DOS EMM386, it would use this instead of the built-in XMS manager. Using an external and possibly customized XMS driver could help overcome issues with BIOS memory reporting functions causing the memory manager not to see all available memory, and on machines using non-standard gate-A20 switching methods, whereas using the internal XMS driver EMM386 could take advantage of speed-optimized 32-bit code for the XMS driver and relocate all but a tiny stub of the XMS driver into Extended Memory. DR-DOS EMM386 could fill "free" areas with UMBs or map RAM over unused ROM areas in virtual mode, provide support for DPMI
(and - in some special issues - DPMS
), and load the support for pre-emptive multitasking and multithreading components of the operating system.
While popular when DOS programs were the mainstream, QEMM eventually became largely irrelevant as Windows programs replaced DOS programs for most users. On the other hand, some of the DOS users switched to operating systems unsupported by QEMM, such as Windows NT
series and Linux
.
The final version was QEMM 97, which was compatible with Windows 95
and later Windows 98
/ME
, but by this point, not only was DOS memory management no longer in high demand, but the remaining competitive DOS applications (including various GNU
utilities, text editors) support EMS, XMS, or DPMI - which reduced demand for conventional memory - or had been ported to Windows 95 or higher. The availability of increasing RAM sizes at low cost served to reduce the need of MagnaRAM. Finally, modern PCI chipsets provide documented functionality to remove write protection from unused UMA; in many or most cases, this last fact eliminates the need for QEMM for even those relatively few users who use DOS applications and who might otherwise find QEMM essential.
Memory manager
In IBM PC compatible computing, DOS memory management refers to software and techniques employed to give applications access to more than 640K of "conventional memory". The 640kB limit was specific to the IBM PC and close compatibles; other machines running MS-DOS had different limits, for example...
produced by Quarterdeck Office Systems
Quarterdeck Office Systems
Quarterdeck Office Systems, later Quarterdeck Corporation , was an American computer software company. It was founded by Therese Myers and Gary Pope in 1981and incorporated in 1982...
in the late 1980s through late 1990s. It was the most popular memory manager for the MS-DOS
MS-DOS
MS-DOS is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating...
and other DOS
DOS
DOS, short for "Disk Operating System", is an acronym for several closely related operating systems that dominated the IBM PC compatible market between 1981 and 1995, or until about 2000 if one includes the partially DOS-based Microsoft Windows versions 95, 98, and Millennium Edition.Related...
operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
s.
QEMM product ranges
QRAM: A memory manager for 286 or higher CPU. It supports Chips and TechnologiesChips and Technologies
Chips and Technologies was the first fabless semiconductor company, a model developed by its founder Gordon Campbell. Founded by Dado Banatao.Its first product was an EGA IBM compatible graphics chip...
chipset
Chipset
A chipset, PC chipset, or chip set refers to a group of integrated circuits, or chips, that are designed to work together. They are usually marketed as a single product.- Computers :...
s. 2.02 added SHADOWRAM switch. QEXT now correctly reallocates XMS. It includes VIDRAM, Optimize, LOADHI from QEMM 6.02, Manifest 1.13.
QEMM Game Edition: It is a version of QEMM that includes Quarterdeck GameRunner. Patches for regular QEMM do not work on QEMM Game Edition.
QEMM MegaBundle: In the version shipped with SideKick for Windows, it is a version with SideBar 1.00 (1994-08-22) and QEMM 7.5.
DESQview 386: It includes DESQview
DESQview
DESQview was a text mode multitasking program developed by Quarterdeck Office Systems which enjoyed modest popularity in the late 1980s and early 1990s...
and QEMM-386.
Competitors
The principal competitors of QEMM were BlueMax/386MAX386MAX
386MAX was a computer memory manager for DOS-based personal computers. It competed with Quarterdeck's QEMM memory manager. It was manufactured by Qualitas....
, and HeadRoom/NetRoom.
Compaq
Compaq
Compaq Computer Corporation is a personal computer company founded in 1982. Once the largest supplier of personal computing systems in the world, Compaq existed as an independent corporation until 2002, when it was acquired for US$25 billion by Hewlett-Packard....
DOS 3.31, released in November 1987, was the first DOS operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
to bundle technology similar to QEMM-386, incorporating a 386-mode EMS manager called CEMM
CEMM
CEMM, for Compaq Expanded Memory Manager was the first so-called PC "memory manager" for Intel 80386 CPUs, able to transform "XMS" extended memory into "EMS" expanded memory by using the virtual memory features and the virtual 8086 mode of the CPU....
. QEMM was the first V86 memory manager on the market.
QEMM driver
QEMM provides access to the Upper Memory AreaUpper Memory Area
In DOS memory management, the upper memory area refers to memory between the addresses of 640 KB and 1024 KB in an IBM PC or compatible. IBM reserved the uppermost 384 KB of the 8088 CPU's 1024 KB address space for ROM, RAM on peripherals, and memory-mapped input/output...
(UMA), expanded memory
Expanded memory
In DOS memory management, expanded memory is a system of bank switching introduced April 24, 1985 that provided additional memory to DOS programs beyond the limit of conventional memory. Expanded memory uses parts of the address space normally dedicated to communication with peripherals for program...
(EMS) and extended memory
Extended memory
In DOS memory management, extended memory refers to memory above the first megabyte of address space in an IBM PC or compatible with an 80286 or later processor. The term is mainly used under the DOS and Windows operating systems...
(XMS), Virtual Control Program Interface
Virtual Control Program Interface
In computing, the Virtual Control Program Interface is a specification published in 1989 by Phar Lap Software that allows a DOS program to run in protected mode, granting access to many features of the processor not available in real mode...
and DOS Protected Mode Interface
DOS Protected Mode Interface
In computing, the DOS Protected Mode Interface is a specification introduced in 1989 which allows a DOS program to run in protected mode, giving access to many features of the processor not available in real mode...
.
- Quickboot: It allows warm reboot to be done without encountering BIOS screen.
DOS-Up
It relocates DOS kernel, COMMAND.COM interpreter, DOS resources (eg: buffers, file handles, stacks, lastdrive). It supports DOS 3.2 or higher.HOOKRAM
It allows drivers to be loaded before loading QEMM and still allow the use of QEMM's Stealth feature.MagnaRAM
It is a memory compression utility for Windows 3.1, Windows For Workgroups, Windows 95. MagnaRAM is included with QEMM 97.MagnaRAM was also released as a separate utility.
MagnaRAM worked by replacing a portion of Windows' virtual memory
Virtual memory
In computing, virtual memory is a memory management technique developed for multitasking kernels. This technique virtualizes a computer architecture's various forms of computer data storage , allowing a program to be designed as though there is only one kind of memory, "virtual" memory, which...
system. MagnaRAM would insert itself in the string of Windows Programs that determined what pieces of RAM will be moved to the hard disk. Instead of writing directly to the hard disk, the information to be written would go to MagnaRAM's own buffer as this was a faster process. During CPU idle, MagnaRAM would compress the information in its own RAM buffer. When the RAM buffer becomes full, it is then swapped to the hard disk taking both less time and less space.
Manifest
First released in 1990-01-11, it is a hardware information utility that displays information about user's system.- 1.11 fixed minor cosmetic bugs.
- 1.12 can identify PS/2 Model 57SX, Compaq Deskpro 486s/16M, Sharp MZ-100. Available EMS in System Overview screen was corrected when using Stealth.
- 1.13 fixed Award BIOS identification problem.
- Version 2.0 provides information on network, enhance reporting of video capabilities, APM, DPMI/VCPI/EMS/XMS memory. New feature include editing DOS and Windows boot configuration files.
Optimize
Similar to Memmaker, it is a utility that calculates, and allows user to choose optimal orders of loading drivers and TSRs. However, OPTIMIZE allows preview of adjustments be made without rebooting. It was first release in 1990-01-11.It is shipped with QEMM and DESQView.
QEMM 50/60
It is a version of QEMM driver for IBM PS/2 Model 50 and 60.Version 4.03 supports IBM Memory Expansion Option boards with 2-8MB memory.
Stealth
It can relocate memory assigned for CGA character set away from UMA.Beginning with QEMM version 8, it allows ROM contents in UMA to be relocated to provide more memory for TSRs. Additional Stealth Windows compatibility is provided with VxDs.
Stealth DoubleSpace/D*Space
Stealth D*Space allows DoubleSpace or DriveSpace to be loaded high.Vidram
First released in 1990-01-10, it can provide extra conventional memory in text mode programs, by reclaiming buffers located in UMA that are used in graphics modes. It requires EGA/VGA-comptible video card.VIDRAMEMS supports DMA-based video memory access at the expense of EMS memory for buffer.
Device driver limit
LOADHI.SYS loads up to 1 device driver at a time in QEMM 4.23, 2 in QEMM 5, 32 in QEMM 6.MagnaRAM limit
Maximum compression threshold setting is 100% for all versions of MagnaRAM 2.00-2.02, except for MagnaRAM 2.00 included with QEMM 8.00, which has the maximum setting of 80%.Memory limit
- QEMM 6.0 can manage up to 128MB EMS, 64MB XMS.
- QEMM 6.02 can manage up to 128MB EMS, 128MB XMS. EMBMEM (16-bit) parameter limit was removed.
- QEMM 7.0 to 7.03 can manage up to 82MB memory.
- QEMM 7.04 can manage up to 256MB memory.
- QEMM 7.5 can manage up to 256MB EMS/XMS.
By default, QEMM 8.0 only provides total up to 64MB XMS, EMS and VCPI memory, unless USERAM= parameter is used.
QEMM only provides total up to 256MB XMS, EMS and VCPI memory.
Optimize limit
Versions up to QEMM 6.01 can process batch files up to 9KB, and 20KB in QEMM 6.02.Batch file line limit is 512 for QEMM versions up to 6.02.
Stealth DoubleSpace/D*Space
Stealth D*Space does not support Windows 95 or later versions of DriveSpace.QEMM History
Originally, the product was called QEMM-386, and was released with a complementary product called QRAM. The 386 suffix was dropped when the Intel Pentium was released.5.0 (1990-01-11)
- LOADHI.SYS now loads 2 device drivers at a time.
- New QEMM parameters include COMPAQ386S (C386S).
5.1 (1990-08)
- QEMM supports moving and reallocating extended memory block, Virtual DMA Services specification.
- QEMM supports systems with large memory cache.
6.0
- New features include Stealth.
- New utilities include HOOKROM?.
- LOADHI.SYS now loads 32 device drivers at a time.
- Manifest was updated to 1.10.
6.01
- QEMM supports loading XMS driver before QEMM, running Stealth in Windows 3.0 in 386 Enhanced mode.
- Optimize support indented CALL statements in batch files.
- Manifest was updated to 1.11.
6.02
It supports 2.88MB floppy drives. New Optimize switches include /COMMANDFILE (CMD), /LOADLOW (LOW), /QUICK (Q). Optimize supports default OPTIMIZE.EXC exclusion file.New QEMM parameters include DISKBUFFRAME=xx (DBF), EXCLUDESTEALTHINT=xx (XSTI), SHADOWRAM=xxx (SH), UNMAPFREEPAGES=Y/N (UFP), WINSHRINKUMBS=N (WSU)
By default, EMS is unmapped when Stealth is active.
Optimize can support batch file up to 20KB.
The 64MB limit was removed from EMBMEM (EMB) parameter.
TESTBIOS's 'Dan and Larry' messages were removed.
Manifest was updated to 1.13.
Vidram now support systems with over 640KB conventional memory under DOS 5 and had not allocated UMBs.
Vidram later than 6.04 uses EMS by default.
7.0
QEMM was rewritten with 32-bit code. Improved adapter RAM detection. Added configuration file support.New features include DOS-Up, Stealth ROM, Stealth DoubleSpace.
New utilities include SWAPECHO.COM, OPTIMIZE.EXE (replaced OPTIMIZE.COM), QDPMI (Quarterdeck DPMI 0.9 host), QSETUP (QEMM Setup for Windows), SCANMEM.COM (USERAM= memory scanner).
Updated utilities include Manifest 2.0.
Addd support of Virtual Mode Extensions and Page Size Extensions found in Pentium, later Intel 80486, or later CPUs; Bus-Mastering hard drives.
Optimize supports disk compression software, DOS 6 multi-config, AUTOEXEC.BAT IF statements.
Vidram can now operate in Windows Enhanced mode DOS windows.
QEMM 7.0x loads itself to shadow RAM by default.
7.02
VIDRAM no longer suppress Int 10, function 1B calls.New Optimize switches include /NOFLUSH (/NOFL).
Stealth DoubleSpace virtualizes DOS Function 9.
DOSDATA improves compatibility with Stacker 3.1, supports PC-DOS 6.1 and XTRADRIVE or OS/2 2.x Boot Manager.
Stealth Windows driver was updated to 7.02.
QEMM driver now supports Compaq 20/e and 25/e.
7.04
DOS-Up now supports Novell DOS 7. In DR-DOS 6 and Novell DOS 7, only DOS resource is loaded high. Improved VCPI compatibility on systems with large amounts of memory. QEMM supports DESQView/X 2.0 server. Manifest now recgonizes STB processors.7.5
New features include Stealth D*Space (replacing Stealth DoubleSpace). New tools include QPI.VXD. Improved Pentium support with DigiSpeech Portable Sound parallel port sound card. QEMM 7.5 no longer loads itself to shadow RAM.97/9.0
Added Windows 95 support. New utilities include MagnaRAM, Manifest for Windows 95. Additional Windows 95 features include optimizing paging file.DOS equivalents
Microsoft released comparable but simpler memory managers of its own - HIMEM.SYS for XMS and EMM386.EXE for EMS with MS-DOS 4.01 in 1989; earlier Windows/386 2.1Windows 2.0
Windows 2.0 is a 16-bit Microsoft Windows GUI-based operating environment that was released on December 9, 1987 and is the successor to Windows 1.0. With Windows 2.1x in 1988, Windows 2.0 was supplemented by Windows/286 and Windows/386...
included a built-in EMM which offered EMS to DOS windows during Windows sessions only. These versions could not yet create Upper Memory Blocks. Digital Research
Digital Research
Digital Research, Inc. was the company created by Dr. Gary Kildall to market and develop his CP/M operating system and related products. It was the first large software company in the microcomputer world...
's DR-DOS
DR-DOS
DR-DOS is an MS-DOS-compatible operating system for IBM PC-compatible personal computers, originally developed by Gary Kildall's Digital Research and derived from Concurrent PC DOS 6.0, which was an advanced successor of CP/M-86...
5.0 (1990) was the first non-vendor-specific DOS to offer the UMB technology, incorporating a 386-mode XMS/EMS manager also called EMM386
EMM386
The name EMM386 was used for the expanded memory managers of both Microsoft's MS-DOS and Digital Research's DR-DOS, which created expanded memory using extended memory on Intel 80386 CPUs. There also is an EMM386.EXE available in FreeDOS....
. It could also allocate some of the video memory or EMS memory as UMB memory. MS-DOS finally offered UMBs in 1991 with version 5.0. MS-DOS's EMM386 required HIMEM to be loaded first, while DR-DOS's EMM386 fulfilled both roles and did not need a separate XMS driver, which was still provided but only needed on 80286-based machines (originally named HIDOS.SYS, later HIMEM.SYS). If an XMS driver was loaded before DR-DOS EMM386, it would use this instead of the built-in XMS manager. Using an external and possibly customized XMS driver could help overcome issues with BIOS memory reporting functions causing the memory manager not to see all available memory, and on machines using non-standard gate-A20 switching methods, whereas using the internal XMS driver EMM386 could take advantage of speed-optimized 32-bit code for the XMS driver and relocate all but a tiny stub of the XMS driver into Extended Memory. DR-DOS EMM386 could fill "free" areas with UMBs or map RAM over unused ROM areas in virtual mode, provide support for DPMI
DOS Protected Mode Interface
In computing, the DOS Protected Mode Interface is a specification introduced in 1989 which allows a DOS program to run in protected mode, giving access to many features of the processor not available in real mode...
(and - in some special issues - DPMS
DOS Protected Mode Services
DOS Protected Mode Services is a set of extended DOS memory management services to allow DPMS-enabled DOS drivers to load and execute in extended memory and protected mode....
), and load the support for pre-emptive multitasking and multithreading components of the operating system.
Windows transition / Decline of QEMM
When Microsoft finally automated the process of UMB optimisation in MS-DOS 6 with the memmaker utility, QEMM's market share began to slide.While popular when DOS programs were the mainstream, QEMM eventually became largely irrelevant as Windows programs replaced DOS programs for most users. On the other hand, some of the DOS users switched to operating systems unsupported by QEMM, such as Windows NT
Windows NT
Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It was a powerful high-level-language-based, processor-independent, multiprocessing, multiuser operating system with features comparable to Unix. It was intended to complement...
series and Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
.
The final version was QEMM 97, which was compatible with Windows 95
Windows 95
Windows 95 is a consumer-oriented graphical user interface-based operating system. It was released on August 24, 1995 by Microsoft, and was a significant progression from the company's previous Windows products...
and later Windows 98
Windows 98
Windows 98 is a graphical operating system by Microsoft. It is the second major release in the Windows 9x line of operating systems. It was released to manufacturing on 15 May 1998 and to retail on 25 June 1998. Windows 98 is the successor to Windows 95. Like its predecessor, it is a hybrid...
/ME
Windows Me
Windows Millennium Edition, or Windows Me , is a graphical operating system released on September 14, 2000 by Microsoft, and was the last operating system released in the Windows 9x series. Support for Windows Me ended on July 11, 2006....
, but by this point, not only was DOS memory management no longer in high demand, but the remaining competitive DOS applications (including various GNU
GNU
GNU is a Unix-like computer operating system developed by the GNU project, ultimately aiming to be a "complete Unix-compatible software system"...
utilities, text editors) support EMS, XMS, or DPMI - which reduced demand for conventional memory - or had been ported to Windows 95 or higher. The availability of increasing RAM sizes at low cost served to reduce the need of MagnaRAM. Finally, modern PCI chipsets provide documented functionality to remove write protection from unused UMA; in many or most cases, this last fact eliminates the need for QEMM for even those relatively few users who use DOS applications and who might otherwise find QEMM essential.
See also
- Real modeReal modeReal mode, also called real address mode, is an operating mode of 80286 and later x86-compatible CPUs. Real mode is characterized by a 20 bit segmented memory address space and unlimited direct software access to all memory, I/O addresses and peripheral hardware...
- Unreal modeUnreal modeIn x86 computing, unreal mode, also big real mode, huge real mode, or flat real mode, is a variant of real mode , in which one or more data segment registers have been loaded with 32-bit addresses and limits. Contrary to its name, it is not a separate addressing mode that the x86-32 and x86-64...
- Protected modeProtected modeIn computing, protected mode, also called protected virtual address mode, is an operational mode of x86-compatible central processing units...
- Conventional memoryConventional memoryIn DOS memory management, conventional memory, also called base memory, is the first 640 kilobytes of the memory on IBM PC or compatible systems. It is the read-write memory usable by the operating system and application programs...
- Extended memoryExtended memoryIn DOS memory management, extended memory refers to memory above the first megabyte of address space in an IBM PC or compatible with an 80286 or later processor. The term is mainly used under the DOS and Windows operating systems...
(XMS) - Expanded memoryExpanded memoryIn DOS memory management, expanded memory is a system of bank switching introduced April 24, 1985 that provided additional memory to DOS programs beyond the limit of conventional memory. Expanded memory uses parts of the address space normally dedicated to communication with peripherals for program...
(EMS) - High Memory Area (HMA)
- DESQviewDESQviewDESQview was a text mode multitasking program developed by Quarterdeck Office Systems which enjoyed modest popularity in the late 1980s and early 1990s...