Editing QEMM (section)

==Features/tools==

===QEMM driver{{anchor|Quickboot}}===
[[File:Quarterdeck Expanded Memory Manager.jpg|thumb|right|QEMM for 80386 and [[IBM Personal System/2|IBM PS/2]] personal computers]]
QEMM provides access to the [[Upper Memory Area]] (UMA) and memory through the [[Expanded Memory Specification]] (EMS), [[Extended Memory Specification]] (XMS), [[Virtual Control Program Interface]] (VCPI) and [[DOS Protected Mode Interface]] (DPMI).

*Quickboot: It allows a form of [[warm reboot]] or [[local reboot]] to be performed without going through the [[BIOS]]. It will therefore completely bypass the [[Power-on self-test|POST]], including the BIOS startup screen and the time-consuming memory test and device enumeration, and just restore the CPU state and interrupts to their initial state after POST.

===DOS-Up===
It relocates DOS kernel, COMMAND.COM interpreter, DOS resources (e.g.: 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 was a [[virtual memory compression]] utility for [[Windows 3.1]], [[Windows For Workgroups]] and [[Windows 95]]. [[MagnaRAM]] is included with QEMM 97.

MagnaRAM was also released as a separate utility.<ref>[http://www.highbeam.com/doc/1G1-17486617.html Article: QUARTERDECK SHIPS MAGNARAM 2: CROSS-PLATFORM MEMORY MULTIPLIER FOR WINDOWS] {{Dead link|date=June 2016}}</ref>

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.<ref>[http://www.ciao.co.uk/Quarterdeck_MagnaRAM_2_0_Complete_package__5531389#productdetail Quarterdeck MagnaRAM 2.0 Complete package]  {{webarchive|url=https://web.archive.org/web/20090209093304/http://www.ciao.co.uk/Quarterdeck_MagnaRAM_2_0_Complete_package__5531389 |date=February 9, 2009 }}</ref>

==={{anchor|MFT}}Manifest===
Manifest (MFT) 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. Shipped with QEMM and DESQview.

===QDPMI===
QDPMI is a DPMI 0.9 server driver, authored by Dan Spear. It requires 386 CPU and QEMM386.

===QEMM 50/60===
It is a version of QEMM driver for the [[IBM PS/2 Model 50|IBM PS/2 Models 50]] and [[IBM PS/2 Model 60|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.

===T386===
It allows Toshiba laptops to work with QEMM's EMS manager.

===VIDRAM===
*Provides extra conventional memory in text mode programs, by reclaiming buffers located in UMA that are used in graphics modes.
*It requires EGA/VGA-compatible video card.
*VIDRAM EMS supports DMA-based video memory access at the expense of EMS memory for buffer.

===Limitations===

====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 5.0 can manage up to 16&nbsp;MB EMS, 16&nbsp;MB XMS.
* QEMM 6.0 can manage up to 64&nbsp;MB EMS, 64&nbsp;MB XMS.
* QEMM 6.02 can manage up to 128&nbsp;MB EMS, 128&nbsp;MB XMS. EMBMEM (16-bit) parameter limit was removed.
* QEMM 7.0-7.03 can manage up to 128&nbsp;MB EMS, 128&nbsp;MB XMS.
* QEMM 7.04, 7.5, 8.0-8.3 and 97 (aka QEMM 9.0) can manage up to 256&nbsp;MB EMS/XMS.

By default, QEMM 7.04 and above provide up to a total of 64&nbsp;MB RAM shared among XMS, EMS and VCPI memory, unless the USERAM= parameter is used.  For example, to allow access to up to 256&nbsp;MB EMS (or 256&nbsp;MB XMS), specify: QEMM386.SYS USERAM=1M-256M <ref>[http://www.delorie.com/djgpp/v2faq/faq3_10.html 3.10 How to get the most RAM for DJGPP programs?]</ref>

For QEMM 7.04 and above, the maximum addressable RAM is 256&nbsp;MB of memory, shared among XMS, EMS and VCPI memory. Initially, XMS allocates the entire 256&nbsp;MB and shares it with EMS and VCPI as needed, that is, as EMS and VCPI request memory blocks, XMS free memory is reduced by that same amount.<ref>[http://www.computing.net/answers/dos/qemm-problem/16804.html QEMM Problem] {{webarchive|url=https://web.archive.org/web/20090511001053/http://www.computing.net/answers/dos/qemm-problem/16804.html |date=2009-05-11 }}</ref>

====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.