A File Control Block (FCB) is a file system structure in which the state of an open file is maintained. The FCB originates from CP/M and is also present in all versions of MS-DOS. A full FCB is 36 bytes long; in early versions of CP/M, it was 33 bytes. A computer file is a collection of information that is stored in a computer system and can be identified by its full path name. ... CP/M was an operating system originally created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc. ... Microsofts disk operating system, MS-DOS, was Microsofts implementation of DOS, which was the first popular operating system for the IBM PC, and until recently, was widely used on the PC compatible platform. ...

The meanings of several of the fields in the FCB differ between CP/M and MS-DOS, and also depending on what operation is being performed. The following fields have consistent meanings:

A 8. ... In computer science sequential access means that a group of elements (e. ... In computer science, random access is the ability to access a random element of a group in equal time. ...

Usage

In CP/M and MS-DOS 1 (which did not include support for directories), the FCB was the only method of accessing files. When directories were introduced in MS-DOS 2, FCBs were superseded by file handles. In computing, a directory, catalog, or folder, is an entity in a file system which can contain a group of files and/or other directories. ... This article discusses a general notion of reference in computing. ...

FCBs were supported in all versions of MS-DOS and Windows until the introduction of the FAT32 filesystem. Windows 95, Windows 98 and Windows Me do not support the use of FCBs on FAT32 drives, except to read the volume label. This caused some old DOS applications, including Wordstar, to fail under these versions of Windows. Microsoft Windows is the name of several families of proprietary software operating systems by Microsoft. ... File Allocation Table (FAT) is a partially patented file system developed by Microsoft for MS-DOS and was the primary file system for consumer versions of Microsoft Windows up to and including Windows Me. ... Windows 95 is a consumer-oriented graphical user interface-based operating system. ... Windows 98 (codenamed Memphis) is a graphical operating system released on June 25, 1998 by Microsoft and the successor to Windows 95. ... Windows Millennium Edition, or Windows Me (IPA pronunciation: [miː], [ɛm iː]), is a hybrid 16-bit/32-bit graphical operating system released on September 14, 2000 by Microsoft. ... WordStar was a word processor application, published by MicroPro, originally written for the CP/M operating system but later ported to DOS, that enjoyed a dominant market share during the early to mid-1980s. ...

The FCB interface does not work properly on Windows NT, 2000, etc either - WordStar does not function properly on these operating systems. The emulator DOSEMU implements the FCB interface properly, and is one way to run older programs. DOSEMU, alternatively rendered dosemu, is a compatibility layer software package that enables MS-DOS software to run under Linux on x86-based PCs (IBM PC compatible computers). ...