Editing DOSEMU (section)

== Features ==
It uses a combination of [[hardware-assisted virtualization]] features and [[high-level emulation]]. It can thus achieve nearly native speed for 8086-compatible DOS operating systems and applications on [[x86]] compatible processors, and for [[DOS Protected Mode Interface]] (DPMI) applications on [[x86]] compatible processors as well as on [[x86-64]] processors. DOSEMU includes an 8086 processor emulator for use with real-mode applications in x86-64 [[long mode]].

DOSEMU is only available for [[x86]] and [[x86-64]] Linux systems (Linux 3.15 x86-64 systems cannot enter DPMI by default.  This is fixed in 3.16).<ref name="bugs_debian_org">{{cite web|title= #751632 dosemu: DPMI fails to initialize on x86_64 with linux 3.15|url=https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=751632}} 140715 bugs.debian.org</ref>

DOSEMU is an option for people who need or want to continue to use legacy DOS software; in some cases virtualisation is good enough to drive external hardware such as [[Programmer (hardware)|device programmers]] connected to the [[parallel port]]. According to its manual, "dosemu" is a user-level program which uses certain special features of the Linux kernel and the 80386 processor to run DOS in a DOS box. The DOS box, relying on a combination of hardware and software, has these abilities:
* Virtualize all input-output and processor control instructions
* Supports the word size and addressing modes of the iAPX86 processor family's "real mode", while still running within the full protected mode environment
* Trap all [[Disk Operating System|DOS]] and [[Basic Input/Output System|BIOS]] system calls and emulate such calls as needed for proper operation and good performance
* Simulate a hardware environment over which DOS programs are accustomed to having control.
* Provide DOS services through native Linux services; for example, dosemu can provide a virtual hard disk drive which is actually a Linux directory hierarchy.<ref name="dosemu_sourceforge_net">{{cite web|title=The dosemu HOWTO|url=http://dosemu.sourceforge.net/docs/HOWTO/|archive-url=https://archive.today/20121225104014/http://dosemu.sourceforge.net/docs/HOWTO/|url-status=dead|archive-date=2012-12-25}} 090430 dosemu.sourceforge.net</ref>
* [[Application programming interface|API-level]] support for [[PC/TCP Packet Driver|Packet driver]],<ref name="sourceforge_net-dosemu-135_tgz">{{cite web|title=dosemu v1.3.5 source|url=http://prdownloads.sourceforge.net/dosemu/dosemu-1.3.5.tgz?download}} 090430 prdownloads.sourceforge.net src/dosext/net/net/pktnew.c</ref> [[Internetwork Packet Exchange|IPX]], [[Berkeley sockets]] (dosnet).<ref name="sourceforge_dosemu140">{{cite web|title=dosemu v1.4.0 source |date=2007-05-05 |access-date=2016-04-06 |url=http://prdownloads.sourceforge.net/dosemu/dosemu-1.4.0.tgz?download}} src/dosext/net/net/ipx.c src/dosext/net/v-net/dosnet.c</ref><ref name="dosemu_announce140">{{cite web|title=The DOSEMU team is proud to announce DOSEMU 1.4.0 |date=2007-05-05 |access-date=2016-04-06 |url=http://dosemu.org/stable/announce |quote=NetWare and other network connectivity via built-in IPX and pktdrvr support /../ the dosemu-freedos binary package starts a DOS-"C:\>"-Drive 'out-of-the-box' in a normal user's $HOME directory and runs without any further configuration (no root rights needed) |url-status=unfit |archive-url=https://web.archive.org/web/20160315163935/http://dosemu.org/stable/announce |archive-date=March 15, 2016}}</ref>