SYS is an external command of DOS and Microsoft Windows 9x operating systems that is used to make an already formatted medium bootable. It will therefore install a boot sector capable of booting the operating system into the first logical sector of the volume. Further, it will copy the principal DOS system files, that is, the DOS-BIOS (IO.SYS or IBMBIO.COM) and the DOS kernel (MSDOS.SYS or IBMDOS.COM) into the root directory of the target. Due to restrictions in the implementation of the boot loaders in the boot sector and DOS' IO system, these two files must reside in the first two directory entries and be stored at the beginning of the data area under MS-DOS and PC DOS. Depending on version, the whole files or only a varying number of sectors of the DOS-BIOS (down to only three sectors in modern issues of DOS) will have to be stored in one consecutive part. SYS will try to physically rearrange other files on the medium in order to make room for these files in their required locations. This is why SYS needs to bypass the filesystem driver in the running operating system. Other DOS issues such as DR-DOS do not have any such restrictions imposed by the design of the boot loaders, therefore under these systems, SYS will install a DR-DOS boot sector, which is capable of mounting the filesystem, and can then simply copy the two system files into the root directory of the target. SYS will also copy the command line shell (COMMAND.COM) into the root directory.[1] The command can be applied to hard drives and floppy disks to repair or create a boot sector.
Although an article on Microsoft's website says the SYS command was introduced in MS-DOS version 2.0,[2] this is incorrect. SYS actually existed in 86-DOS 0.3 already. According to The MS-DOS Encyclopedia, the command was licensed to IBM as part of the first version of MS-DOS,[3] and as such it was part of MS-DOS/PC DOS from the very beginning (IBM PC DOS 1.0 and MS-DOS 1.25).
See also [link]
References [link]
- ↑ Microsoft DOS sys command
- ↑ SYS.COM Requirements in MS-DOS versions 2.0-6.0
- ↑ Duncan, Ray (1988). The MS-DOS Encyclopedia, Microsoft Press, p. 940. ISBN 1-55615-049-0.
External links [link]
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.sys
.sys is a filename extension in Microsoft Windows and DOS-type operating system.
Most .sys files are real mode device drivers. Certain files using this extension are not, however: MSDOS.SYS and IO.SYS are core operating system files in MS-DOS and Windows 9x. The CONFIG.SYS text file contains various configuration options and specifies what device drivers will be loaded. COUNTRY.SYS is a binary database containing country and codepage related information for use with the CONFIG.SYS COUNTRY directive and the NLSFUNC driver, whereas KEYBOARD.SYS is a binary database containing keyboard layout related information including short P-code sequences to be executed by an interpreter inside the KEYB keyboard driver.
.sys files are mainly stored in the C:\Windows\system32\drivers directory of Windows computers, and also in the C:\Windows\WinSxS folder, particularly in Windows Vista and its successors.
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JPEG
JPEG (/ˈdʒeɪpɛɡ/ JAY-peg) is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography. The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality.
JPEG compression is used in a number of image file formats. JPEG/Exif is the most common image format used by digital cameras and other photographic image capture devices; along with JPEG/JFIF, it is the most common format for storing and transmitting photographic images on the World Wide Web. These format variations are often not distinguished, and are simply called JPEG.
The term "JPEG" is an abbreviation for the Joint Photographic Experts Group, which created the standard. The MIME media type for JPEG is image/jpeg, except in older Internet Explorer versions, which provides a MIME type of image/pjpeg when uploading JPEG images. JPEG files usually have a filename extension of .jpg or .jpeg.
SYS
SYS may indicate:
Command
Command may refer to:
Computing
Military
Sports
Economics and politics
Linguistics and teaching
Command (military formation)
A command in military terminology is an organisational unit for which the individual in Military command is responsible. A Commander will normally be specifically appointed to the role in order to provide a legal framework for the authority bestowed. Naval and military officers have legal authority by virtue of their officer's commission, however the specific responsibilities and privileges of command are derived from the publication of appointment.
The United States Department of Defense defines command as follows:
(DOD) 2. An order given by a commander; that is, the will of the commander expressed for the purpose of bringing about a particular action.
(DOD) 3. A unit or units, an organization, or an area under the command of one individual. Also called CMD. See also area command; combatant command; combatant command (command authority).
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Notes
Command (computing)
In computing, a command is a directive to a computer program acting as an interpreter of some kind, in order to perform a specific task. Most commonly a command is either a directive to some kind of command-line interface, such as a shell, or an event in a graphical user interface triggered by the user selecting an option in a menu.
Specifically, the term command is used in imperative computer languages. These languages are called this, because statements in these languages are usually written in a manner similar to the imperative mood used in many natural languages. If one views a statement in an imperative language as being like a sentence in a natural language, then a command is generally like a verb in such a language.
Many programs allow specially formatted arguments, known as flags or options, which modify the default behaviour of the command, while further arguments describe what the command acts on. Comparing to a natural language: the flags are adverbs, whilst the other arguments are objects.
