DOS (an abbreviation of Disk Operating System “Disk Operating System” or “Operating System Disk”) is a family of operating systems for personal computers (PC). Created for computers of the IBM PC family, they used the 16-bit Intel 8086 and 8088 processors, being the first popular operating system for this platform. It had a command-line interface in text mode or alphanumeric, via its shell, command.com. Probably the most popular of its variants is the belonging to the family MS-DOS, Microsoft, supplied with a good part of the computers compatible with the IBM PC, in particular, those of the family of Intel, as a separate operating system or native, up to version 6.22, often attached to a version of the graphical interface of 16-bit Windows, such as 3.1 x.
Inversions native Microsoft Windows based on NT (and this in turn in OS/2 2.X) (see Windows NT, 2000, 2003, XP or Vista or Windows 7) MS-DOS disappears as operating system (proper) and base environment, from which the computer and its essential processes were started and the windows graphical interface or working environment was run and loaded. Any vestige of the same is relegated, in such versions, to the existence of a simple shell, called System symbol, executed as an application using cmd.exe, from the realistic environment itself (now elevated to the system category).
This is not true for non-native Windows versions, which are MS-DOS-based, and are loaded from it. From 1.0 x to 3.1(1), 16-bit versions, Ms. Windows had the idea of a simple interface application or graphical environment, complementary to the shell itself, from which it was executed. It was from the 32-bit, new design, and higher power versions, based on Windows 95 and 98, that the MS-DOS began to be deliberately camouflaged by the windows graphic environment itself. During the boot process, it is giving way, by default, to its automatic execution, which caught the attention of the average user and attributed to the old system a more dependent and secondary role, becoming by many forgotten and unknown. Gradually abandoned by the software and hardware developers., starting with Microsoft itself (this option can be disabled by altering the BootGUI=1 entry by BootGUI=0, from the system file, now text, MSDOS. SYS). However, in such versions, Windows did not function autonomously, as an operating system. Several of the primary or essential functions of the system and their boot are still due to the 32-bit versions, to the different modules and system files that made up the modest frame of the DOS, requiring those a minimum of the underlying records of the DOS, in order to be run (such as IO.SYS, DRVSPACE. BIN, EMM386.EXE and HIMEM. SYS).
There are several versions of DOS:
- MS-DOS, Microsoft, is the most well-known.
- PC-DOS, IBM.
- DR-DOS, from Digital Research, would then move to Novell (Novell DOS 7.0), then to Caldera and finally to DeviceLogics.
- FreeDOS is the most recent, free license and open source. You can do the version for GNU/Linux and UNIX, of an emulator of MS-DOS under systems of this type.
With the appearance of the operating systems with graphical user interface (GUI), of the Windows type, especially those of 32 bits, of the Windows 95 type, the DOS has been relegated to the background, until being reduced to the mere shell of commands, and to the command lines (especially in type files .PIF and .BAT), as in Windows NT derivative systems.
The story of DOS games started in 1981 when a purchase was made, on the part of Microsoft, the operating system, QDOS (Quick and Dirty Operating System), that after receiving a few modifications, become the first version of the Microsoft operating system, called MS-DOS 1.0 (Microsoft Disk Operating System).
From here, there are a series of modifications to the operating system, until you get to version 7.1, from which MS-DOS ceases to exist as such and becomes an integrated part of the Microsoft Windows operating system.
MS-DOS chronology in all versions
- In 1982, version 1.25 was released, and support for double-sided diskettes was added.
- In 1983, the system began to have more functionality, with its version 2.0, which added support to IBM 10 MB hard drives, and the ability to read-write 5¼” floppy disks with a capacity of 360 Kb. In version 2.11 of the same year, new keyboard characters are added.
- In 1984, Microsoft would release its MS-DOS 3.0 version, and that’s when support for 1.2 MB high-density disks and the possibility of installing a hard drive with a maximum of 32 MB is added. In the same year, support for Microsoft networks would be added to version 3.1.
- Three years later, in 1987, version 3.3 is released with support for 3½” floppy disks, and it is allowed to use hard drives more significant than 32 MB.
- In 1988, Microsoft released its version 4.0 and with it the support for extended memory specification (XMS) and the possibility to include hard drives up to 2 GB, it should be noted that this version was the biggest catastrophe carried out by the company because it was full of bugs, bugs, etc., which they fixed in 1989 with the release of version 4.01 that solved all these problems and failures.
- In 1991, one of the most relevant developments in MS-DOS history is the transition from version 4.01 to version 5.0, in which DOS is already able to load programs into the high memory part of the system using the upper memory (from 640 Kb to 1024 Kb). In version 5.0, the basic programmer and the famous EDIT editor are added. We also added the utilities UNDELETE (recovery of deleted files), FDISK (partition management), and service to run programs designed for earlier versions of MS-DOS, called SERVER. At the end of 1992 was resolved a few problems with UNDELETE and CHKDSK on the 5.0 release.
- In 1993, MS-DOS 6.0 appeared with many new features, among them the Doublespace utility that was responsible for compressing the disk and thus having more space available, also included a basic antivirus (MSAV), a DEFRAGMENTADOR (DEFRAG), a memory administrator (MEMMAKER) and some old utilities were suppressed, which by misusing them could destroy data, these utilities were JOIN and RECOVER, among others. In the same year, version 6.2, which adds safety to the loss of data Doublespace, and adds a new scanner, disk, SCANDISK, and solves problems with DISKCOPY and SmartDrive. In version 6.21, which appeared in 1993, Microsoft suppresses Doublespace and looks for a new alternative for this utility.
- In 1994, the solution to the Doublespace problem appeared was the utility of the company Stac Electronics, Drive space, the one chosen to be included in version 6.22.
- In 1995 Microsoft Windows 95 appeared, and with the appearance of the same, means to separate MS-DOS to a secondary plane.
The MS-DOS system, however, remains in 1995 a new version, 7.0, which correct a multitude of utilities and provides support for long names. Deleted services from the previous operating system can be found in the Windows 95 \other\oldmsdos CD directory.
In 1997 Windows 95 OSR2 appeared and with it a comprehensive revision of system DOS, adding support for FAT32 partitions. Since then, MS-DOS ceases to exist as an operating system.
Several companies developed versions of DOS, generally very similar to each other. PC-DOS and MS-DOS, for example, began to be virtually identical, although they ended up being very different. Versions most well-known are QDOS, PC-DOS, MS-DOS, and FreeDOS, among others.
With the GNU / Linux operating system, it is possible to run two copies under DOSEmu, a virtual machine native to GNU/Linux to run programs in real mode. There are many other emulators for different versions of UNIX, even for platforms other than the x86 processor architecture.