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Xip
In computer science, execute in place (XIP) is a method of executing programs directly from long-term storage rather than copying it into random-access memory, RAM. It is an extension of using shared memory to reduce the total amount of memory required. Its general effect is that the program text consumes no writable memory, saving it for dynamic data, and that all instances of the program are run from a single copy. For this to work, several criteria have to be met: * The storage must provide a similar interface to the Central processing unit, CPU as regular memory (or an adaptive layer must be present). * This interface must provide sufficiently fast read operations with a random access pattern. * The file system, if one is used, needs to expose appropriate mapping functions. * The program must either be Linker (computing), linked to be aware of the address the storage appears at in the system or be Position-independent code, position-independent. * The program must not modify ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flash Memory
Flash memory is an Integrated circuit, electronic Non-volatile memory, non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash, are named for the NOR gate, NOR and NAND gate, NAND logic gates. Both use the same cell design, consisting of floating-gate MOSFETs. They differ at the circuit level, depending on whether the state of the bit line or word lines is pulled high or low; in NAND flash, the relationship between the bit line and the word lines resembles a NAND gate; in NOR flash, it resembles a NOR gate. Flash memory, a type of floating-gate memory, was invented by Fujio Masuoka at Toshiba in 1980 and is based on EEPROM technology. Toshiba began marketing flash memory in 1987. EPROMs had to be erased completely before they could be rewritten. NAND flash memory, however, may be erased, written, and read in blocks (or pages), which generally are much smaller than the entire devi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NAND Flash Memory
Flash memory is an electronic non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash, are named for the NOR and NAND logic gates. Both use the same cell design, consisting of floating-gate MOSFETs. They differ at the circuit level, depending on whether the state of the bit line or word lines is pulled high or low; in NAND flash, the relationship between the bit line and the word lines resembles a NAND gate; in NOR flash, it resembles a NOR gate. Flash memory, a type of floating-gate memory, was invented by Fujio Masuoka at Toshiba in 1980 and is based on EEPROM technology. Toshiba began marketing flash memory in 1987. EPROMs had to be erased completely before they could be rewritten. NAND flash memory, however, may be erased, written, and read in blocks (or pages), which generally are much smaller than the entire device. NOR flash memory allows a single machine word to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AXFS
AXFS (Advanced XIP Filesystem) is a compressed read-only file system for Linux, initially developed at Intel, and now maintained at Numonyx. It was designed to use execute in place (XIP) alongside compression aiming to reduce boot and program load times, while retaining a small memory footprint for embedded devices. This is achieved by mixing compressed and uncompressed pages in the same executable file. AXFS is free software licensed under the GPL. Cramfs is another read-only compressed file system that supports XIP (with patches); however, it uses a strategy of decompressing entire files, whereas AXFS supports XIP with page granularity.Justin Treon, (2008-05-09) ', LinuxDevices.com, "There are two XIP-enabled Linux filing systems that can be used for a Balanced XIP implementation: Linear XIP CRAMFS and AXFS. The Linear XIP CRAMFS decompresses files on a file-by-file basis, whereas AXFS decompresses files on a page-by-page basis offering more optimal Flash usage." See ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Science
Computer science is the study of computation, information, and automation. Computer science spans Theoretical computer science, theoretical disciplines (such as algorithms, theory of computation, and information theory) to Applied science, applied disciplines (including the design and implementation of Computer architecture, hardware and Software engineering, software). Algorithms and data structures are central to computer science. The theory of computation concerns abstract models of computation and general classes of computational problem, problems that can be solved using them. The fields of cryptography and computer security involve studying the means for secure communication and preventing security vulnerabilities. Computer graphics (computer science), Computer graphics and computational geometry address the generation of images. Programming language theory considers different ways to describe computational processes, and database theory concerns the management of re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Das U-Boot
Das U-Boot (subtitled "the Universal Boot Loader" and often shortened to U-Boot; see ''#History, History'' for more about the name) is an open-source software, open-source Bootloader, boot loader used in Embedded system, embedded devices to perform various low-level hardware initialization tasks and boot the device's operating system kernel. It is available for a number of computer architectures, including Motorola 68000 series, M68000, ARM architecture, ARM, Blackfin, MicroBlaze, AArch64, MIPS architecture, MIPS, Nios II, SuperH, PowerPC, PPC, Power ISA, RISC-V, LoongArch and x86 architecture, x86. Functionality U-Boot is both a first-stage and second-stage bootloader. It is loaded by the system's ROM (e.g. on-chip ROM of an ARM CPU) from a supported boot device, such as an SD card, SATA drive, NOR flash (e.g. using Serial Peripheral Interface Bus, SPI or I²C), or NAND flash. If there are size constraints, U-Boot may be split into two stages: the platform would load a small ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ottawa Linux Symposium
The Linux Symposium was a Linux and open source conference held annually in Canada from 1999 to 2014. The conference was initially named Ottawa Linux Symposium and was held only in Ottawa, but was renamed after being held in other cities in Canada. Even after the name change, however, it was still referred to as OLS. The conference featured 100+ paper presentations, tutorials, birds of a feather sessions and mini summits on a wide range of topics. There were 650 attendees from 20+ countries in 2008. History The 2009 Symposium was held in Montréal, Quebec. The 2011 and 2012 Symposium were both held in Ottawa. In 2014, OLS organizers put together an unsuccessful campaign on Indiegogo to raise funds in order to pay off debts from previous events. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Firmware
In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computer, computing machinery. It includes the study and experimentation of algorithmic processes, and the development of both computer hardware, hardware and softw ..., firmware is software that provides low-level control of computing device Computer hardware, hardware. For a relatively simple device, firmware may perform all control, monitoring and data manipulation functionality. For a more complex device, firmware may provide relatively low-level control as well as hardware abstraction Service (systems architecture), services to higher-level software such as an operating system. Firmware is found in a wide range of computing devices including personal computers, smartphones, home appliances, vehicles, computer peripherals and in many of the integrated circuits inside each of these larger systems. Firmware is stored in non-volatile memory either read-only memory (ROM) or progra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comparison Of File Systems
The following tables compare general and technical information for a number of file systems. General information Metadata All widely used file systems record a last modified time stamp (also known as "mtime"). It is not included in the table. Individual file systems may record additional special types of date and time stamps. For example, the specification of ISO 9660 includes a "File Expiration Date and Time" and a "File Effective Date and Time". Features File capabilities Block capabilities Note that in addition to the below table, block capabilities can be implemented below the file system layer in Linux (Logical Volume Manager (Linux), LVM, , Dm-crypt#cryptsetup, cryptsetup) or Windows (Volume Shadow Copy Service, SECURITY.BIN, SECURITY), etc. Resize capabilities "Online" and "offline" are synonymous with "mounted" and "not mounted". Allocation and layout policies OS support Limits While storage devices usually have their size ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NetBSD
NetBSD is a free and open-source Unix-like operating system based on the Berkeley Software Distribution (BSD). It was the first open-source BSD descendant officially released after 386BSD was fork (software development), forked. It continues to be actively developed and is available for many platforms, including servers, desktops, handheld devices, and embedded systems. The NetBSD project focuses on code clarity, careful design, and portability across many computer architectures. Its source code is publicly available and Permissive free software licence, permissively licensed. History NetBSD was originally derived from the 4.3BSD-Reno release of the Berkeley Software Distribution from the Computer Systems Research Group of the University of California, Berkeley, via its Net/2 source code release and the 386BSD project. The NetBSD project began as a result of frustration within the 386BSD developer community with the pace and direction of the operating system's development. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
User Space And Kernel Space
A modern computer operating system usually uses virtual memory to provide separate address spaces or regions of a single address space, called user space and kernel space. This separation primarily provides memory protection and hardware protection from malicious or errant software behaviour. Kernel space is strictly reserved for running a privileged operating system kernel, kernel extensions, and most device drivers. In contrast, user space is the memory area where application software and some drivers execute, typically with one address space per process. Overview The term user space (or userland) refers to all code that runs outside the operating system's kernel. User space usually refers to the various programs and libraries that the operating system uses to interact with the kernel: software that performs input/output, manipulates file system objects, application software, etc. Each user space process usually runs in its own virtual memory space, and, unless explicitl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MOS Technology 6532
The 6532 RAM-I/O-Timer (RIOT) was an integrated circuit made by MOS Technology, as well as second sources such as Rockwell. It incorporates 128 bytes of static RAM, two bidirectional 8-bit digital input/output ports, and a 8-bit Programmable interval timer (with pre-divider). This high degree of integration made it popular in the late 1970s and early 1980s, as it could take the place of several different integrated circuits (ICs). It is used in the Atari 2600 video game console. The chip was also deployed in Gottlieb pinball machines, such as ''Haunted House'' and ''Black Hole'', the Atari 810 and 1050 disk drives, as well as Commodore's 8050, 8250 & 8250LP PET disk drives. The Atari 850 Interface, which gives the Atari 400 and 800 computers an RS-232 interface, uses two 6532 chips. 6532 ICs were available in 1 MHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
