Civil Rights
Movements, leaders, victories and the continuing fight for equality.
q2K BHP
Black History Portal
THE BHP WIRE —
HIDDEN TRUTHS
What's New!
Explore the people, places, events, achievements, struggles and stories that shaped our journey.
Movements, leaders, victories and the continuing fight for equality.
Innovation, patents, science, technology and world-changing contributions.
Pioneers, champions, Negro Leagues, records, activism and excellence.
Meet the people whose lives, choices and achievements shaped the journey.
Black towns, communities, institutions and places where history happened.
Moments that changed communities, movements, institutions and the nation.
Mansa Musa was the ruler of the Mali Empire in West Africa. Details recorded here should be sourced; unknown information is left blank.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
 | This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these messages)
|
The Job File Table (JFT) is an MS-DOS data structure in the Program Segment Prefix (PSP). It starts at PSP offset 0x18 and is 20 bytes long. For each open file handle, DOS stores the index into the System File Table (SFT). A file handle that is returned by open, _open, and other similar functions is simply an index into the JFT where DOS stored the SFT entry index for the file or device that the program opened.
When a program starts, the first 5 entries in the JFT are preconnected to the standard devices. All other handles are marked as closed by setting the value of the entry to 0xFF. The standard devices are initialised as follows:
| Handle | Description |
|---|---|
| 0 | Standard input |
| 1 | Standard output |
| 2 | Standard error |
| 3 | COM1 |
| 4 | LPT1 |
Handles 0-2 are connected to the console device. During program execution they can get modified (closed, redirected) like any other handle.
Because the size of the JFT in the PSP is limited to 20 bytes, originally only 15 files (20 minus the 5 standard devices) could be open at a time. In MS-DOS 2.0, the Extended Job File Table was introduced, which allowed up to 254 files to be opened.
As of MS-DOS 3.30, the size of the JFT can be modified with a call to INT 21h, 67h.
Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
The Job File Table (JFT) is an MS-DOS data structure in the Program Segment Prefix (PSP). It starts at PSP offset 0x18 and is 20 bytes long. For each open file handle, DOS stores the index into the System File Table (SFT). A file handle that is returned by open, _open, and other similar functions is simply an index into the JFT where DOS stored the SFT entry index for the file or device that the program opened. When a program starts, the first 5 entries in the JFT are preconnected to the standard devices. All other handles are marked as closed by setting the value of the entry to 0xFF. The standard devices are initialised as follows: Handles 0-2 are connected to the console device. During program execution they can get modified (closed, redirected) like any other handle. Because the size of the JFT in the PSP is limited to 20 bytes, originally only 15 files (20 minus the 5 standard devices) could be open at a time. In MS-DOS 2.0, the Extended Job File Table was introduced, which allowed up to 254 files to be opened. As of MS-DOS 3.30, the size of the JFT can be modified with a call to INT 21h, 67h.
In computer science, a resource leak is a particular type of resource consumption by a computer program where the program does not release resources it has acquired. This condition is normally the result of a bug in a program. Typical resource leaks include memory leak and handle leak, particularly file handle leaks, though memory is often considered separately from other resources. Examples of resources available in limited numbers to the operating system include internet sockets, file handles, process table entries, and process identifiers (PIDs). Resource leaks are often a minor problem, causing at most minor slowdown and being recovered from after processes terminate. In other cases resource leaks can be a major problem, causing resource starvation and severe system slowdown or instability, crashing the leaking process, other processes, or even the system. Resource leaks often go unnoticed under light load and short runtimes, and these problems only manifest themselves under heavy system load or systems that remain running for long periods of time. Resource leaks are particularly a problem for resources available in very low quantities. Leaking a unique resource, such as a lock, is particularly serious, as this causes immediate resource starvation (it prevents other processes from acquiring it) and causes deadlock. Intentionally leaking resources can be used in a denial-of-service attack, such as a fork bomb, and thus resource leaks present a security bug.
In Unix and Unix-like computer operating systems, a file descriptor (FD, less frequently fildes) is a process-unique identifier (handle) for a file or other input/output resource, such as a pipe or network socket. File descriptors typically have non-negative integer values, with negative values being reserved to indicate "no value" or error conditions. File descriptors are a part of the POSIX API. Each Unix process (except perhaps daemons) should have three standard POSIX file descriptors, corresponding to the three standard streams:
In computer programming, a handle is an abstract reference to a resource that is used when application software references blocks of memory or objects that are managed by another system like a database or an operating system. A resource handle can be an opaque identifier, in which case it is often an integer number (often an array index in an array or "table" that is used to manage that type of resource), or it can be a pointer that allows access to further information. Common resource handles include file descriptors, network sockets, database connections, process identifiers (PIDs), and job IDs. PIDs and job IDs are explicitly visible integers; while file descriptors and sockets (which are often implemented as a form of file descriptor) are represented as integers, they are typically considered opaque. In traditional implementations, file descriptors are indices into a (per-process) file descriptor table, thence a (system-wide) file table.
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →Brown v. Board of Education in 1954.
