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DOS-C
Pasquale "Pat" J. Villani (18 April 1954 – 27 August 2011) was an American computer programmer, author, and advocate of free software, best known for his creation of DOS-C, a DOS emulator written in the C language and subsequently adapted as the kernel (operating system), kernel of the FreeDOS operating system and a number of other projects including DOSEMU for Linux. He used to sign his edits with siglum "patv". FreeDOS involvement Villani had already been working on a DOS-like operating system for use in embedded systems for some while before the advent of FreeDOS. His efforts started when he developed an MS-DOS 3.1-compatible interface emulator to write device drivers in the C high-level language instead of in assembly language, as was the usual approach at that time. This interface emulator grew into a minimal operating system named XDOS around 1988. He added an Initial Program Loader, IPL to set up a boot environment before loading the actual operating system and de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FreeDOS
FreeDOS (formerly PD-DOS) is a free software operating system for IBM PC compatible computers. It intends to provide a complete MS-DOS-compatible environment for running Legacy system, legacy software and supporting embedded systems. FreeDOS can be booted from a floppy disk or USB flash drive and is designed to run well under virtualization or x86 Emulator, emulation. The FreeDOS project began under Jim Hall (computer programmer), Jim Hall in 1994, and the first Stable version, stable version was released in 2006. Unlike most versions of MS-DOS, FreeDOS is composed of free software, Software license, licensed under the terms of the GNU General Public License. However, other packages that form part of the FreeDOS project include non-GPL software considered worthy of Digital preservation, preservation, such as 4DOS, which is distributed under a modified MIT License. Distribution FreeDOS 1.1, released on 2 January 2012, is available for download as a CD-ROM image: a limited in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nocera Inferiore
Nocera Inferiore ( or simply , , locally ) is a town and ''comune'' in the province of Salerno, in Campania in southern Italy. It lies west of Nocera Superiore, at the foot of Monte Albino, some 20 km east-southeast of Naples by rail. History The ancient city of ''Nuceria Alfaterna'' was situated nearby in Nocera Superiore. Some of the city's necropoli were located in the area of Nocera Inferiore. Its post-Roman history until 1851 is in common with Nocera Superiore. Post-Roman history At an early date, the city became an episcopal see named ''Nuceria Christianorum'' ('Nocera of the Christians'), and in the 12th century, it sided with Innocent II against Roger II of Sicily, suffering severely for its choice. In the 13th century, and long after, the town had the name of Nocera dei Pagani ('Nocera of the pagans') because a colony of Muslim Saracens was introduced by Frederick II, Holy Roman Emperor, Frederick II in the annexed territory of nowadays Pagani, Campania, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Assembly Language
In computing, assembly language (alternatively assembler language or symbolic machine code), often referred to simply as assembly and commonly abbreviated as ASM or asm, is any low-level programming language with a very strong correspondence between the instructions in the language and the architecture's machine code instructions. Assembly language usually has one statement per machine instruction (1:1), but constants, comments, assembler directives, symbolic labels of, e.g., memory locations, registers, and macros are generally also supported. The first assembly code in which a language is used to represent machine code instructions is found in Kathleen and Andrew Donald Booth's 1947 work, ''Coding for A.R.C.''. Assembly code is converted into executable machine code by a utility program referred to as an '' assembler''. The term "assembler" is generally attributed to Wilkes, Wheeler and Gill in their 1951 book '' The Preparation of Programs for an Electronic Dig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Task Manager
In operating systems, a task manager is a system monitor program used to provide information about the processes and applications running on a computer, as well as the general status of the computer. Some implementations can also be used to terminate processes and applications, as well as change the processes' scheduling priority. In some environments, users can access a task manager with the Control-Alt-Delete keyboard shortcut. Task managers can display running services. ( processes) as well as those that were stopped. They can display information about the services, including their process identifier and group identifier. Common task managers * Activity Monitor, included in macOS * Conky, for the X Window System * htop, for the Unix shell * Plasma System Monitor, included in KDE Plasma Desktop * nmon, for Linux and AIX * ps, for the Unix shell * Task Manager, included in Windows * tasklist, for DOS * TaskManager, included in MorphOS * top, for the Unix shell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DOS Memory Management
In IBM PC compatible computing, DOS memory management refers to software and techniques employed to give applications access to more than 640 kibibytes (640*1024 bytes) (KiB) of "conventional memory". The 640 KiB limit was specific to the IBM PC and close compatibles; other machines running MS-DOS had different limits, for example the Apricot PC could have up to 768 KiB and the Sirius Victor 9000, 896 KiB. Memory management on the IBM family was made complex by the need to maintain backward compatibility to the original PC design and real-mode DOS, while allowing computer users to take advantage of large amounts of low-cost memory and new generations of processors. Since DOS has given way to Microsoft Windows and other 32-bit operating systems not restricted by the original arbitrary 640 KiB limit of the IBM PC, managing the memory of a personal computer no longer requires the user to manually manipulate internal settings and parameters of the system. The 640 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microkernel
In computer science, a microkernel (often abbreviated as μ-kernel) is the near-minimum amount of software that can provide the mechanisms needed to implement an operating system (OS). These mechanisms include low-level address space management, thread (computing), thread management, and inter-process communication (IPC). If the hardware provides multiple Protection ring, rings or CPU modes, the microkernel may be the only software executing at the most privileged level, which is generally referred to as kernel mode, supervisor or kernel mode. Traditional operating system functions, such as device drivers, protocol stacks and file systems, are typically removed from the microkernel itself and are instead run in user space. In terms of the source code size, microkernels are often smaller than monolithic kernels. The MINIX 3 microkernel, for example, has only approximately 12,000 lines of code. History Microkernels trace their roots back to Danish computer pioneer Per Brinch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rewrite (programming)
A rewrite in computer programming is the act or result of re-implementing a large portion of existing functionality without re-use of its source code. When the rewrite uses no existing code at all, it is common to speak of a rewrite from scratch. Motivations A piece of software is typically rewritten when one or more of the following apply: *its source code is not available or is only available under an incompatible license *its code cannot be adapted to a new target platform *its existing code has become too difficult to handle and extend *the task of debugging it seems too complicated *the programmer finds it difficult to understand its source code *developers learn new techniques or wish to do a big feature overhaul which requires much change *the programming language of the source code has to be changed Risks Several software engineers, such as Joel Spolsky have warned against total rewrites, especially under schedule constraints or competitive pressures. While developers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory Model (addressing Scheme)
In computing, a memory address is a reference to a specific memory location in memory used by both software and hardware. These addresses are fixed-length sequences of digits, typically displayed and handled as unsigned integers. This numerical representation is based on the features of CPU (such as the instruction pointer and incremental address registers). Programming language constructs often treat the memory like an array. Types Physical addresses A digital computer's main memory consists of many memory locations, each identified by a unique physical address (a specific code). The CPU or other devices can use these codes to access the corresponding memory locations. Generally, only system software (such as the BIOS, operating systems, and specialized utility programs like memory testers) directly addresses physical memory using machine code instructions or processor registers. These instructions tell the CPU to interact with a hardware component called the memory contro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Instruction Set
In computer science, an instruction set architecture (ISA) is an abstract model that generally defines how software controls the CPU in a computer or a family of computers. A device or program that executes instructions described by that ISA, such as a central processing unit (CPU), is called an ''implementation'' of that ISA. In general, an ISA defines the supported Machine code, instructions, data types, Register (computer), registers, the hardware support for managing Computer memory, main memory, fundamental features (such as the memory consistency, addressing modes, virtual memory), and the input/output model of implementations of the ISA. An ISA specifies the behavior of machine code running on implementations of that ISA in a fashion that does not depend on the characteristics of that implementation, providing binary compatibility between implementations. This enables multiple implementations of an ISA that differ in characteristics such as Computer performance, performa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
8086
The 8086 (also called iAPX 86) is a 16-bit microprocessor chip designed by Intel between early 1976 and June 8, 1978, when it was released. The Intel 8088, released July 1, 1979, is a slightly modified chip with an external 8-bit data bus (allowing the use of cheaper and fewer supporting ICs),Fewer TTL buffers, latches, multiplexers (although the amount of TTL logic was not drastically reduced). It also permits the use of cheap 8080-family ICs, where the 8254 CTC, 8255 PIO, and 8259 PIC were used in the IBM PC design. In addition, it makes PCB layout simpler and boards cheaper, as well as demanding fewer (1- or 4-bit wide) DRAM chips. and is notable as the processor used in the original IBM PC design. The 8086 gave rise to the x86 architecture, which eventually became Intel's most successful line of processors. On June 5, 2018, Intel released a limited-edition CPU celebrating the 40th anniversary of the Intel 8086, called the Intel Core i7-8086K. History Background In 1972 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motorola 68000
The Motorola 68000 (sometimes shortened to Motorola 68k or m68k and usually pronounced "sixty-eight-thousand") is a 16/32-bit complex instruction set computer (CISC) microprocessor, introduced in 1979 by Motorola Semiconductor Products Sector. The design implements a 32-bit instruction set, with 32-bit registers and a 16-bit internal data bus. The address bus is 24 bits and does not use memory segmentation, which made it easier to program for. Internally, it uses a 16-bit data arithmetic logic unit (ALU) and two more 16-bit ALUs used mostly for addresses, and has a 16-bit external data bus. For this reason, Motorola termed it a 16/32-bit processor. As one of the first widely available processors with a 32-bit instruction set, large unsegmented address space, and relatively high speed for the era, the 68k was a popular design through the 1980s. It was widely used in a new generation of personal computers with graphical user interfaces, including the Macintosh 128K, Amiga, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
