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Bank Switching
Bank switching is a technique used in computer design to increase the amount of usable memory beyond the amount directly addressable by the Processor (computing), processor instructions. It can be used to configure a system differently at different times; for example, a read-only memory, ROM required to booting, start a system from diskette could be switched out when no longer needed. In video game systems, bank switching allowed larger games to be developed for play on existing consoles. Bank switching originated in minicomputer systems. Many modern microcontrollers and microprocessors use bank switching to manage random-access memory, non-volatile memory, input-output devices and system management registers in small embedded systems. The technique was common in 8-bit microcomputer systems. Bank-switching may also be used to work around limitations in address bus width, where some hardware constraint prevents straightforward addition of more address lines, and to work around li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CDC 1604
The CDC 1604 is a 48-bit computer designed and manufactured by Seymour Cray and his team at the Control Data Corporation (CDC). The 1604 is known as one of the first commercially successful transistorized computers. (The IBM 7090 was delivered earlier, in November 1959.) Legend has it that the 1604 designation was chosen by adding CDC's first street address (501 Park Avenue) to Cray's former project, the ERA- UNIVAC 1103. A cut-down 24-bit version, designated the CDC 924, was shortly thereafter produced, and delivered to NASA. The first 1604 was delivered to the U.S. Navy Post Graduate School in January 1960 for JOVIAL applications supporting major Fleet Operations Control Centers primarily for weather prediction in Hawaii, London, and Norfolk, Virginia. By 1964, over 50 systems were built. The CDC 3600, which added five op codes, succeeded the 1604, and "was largely compatible" with it. One of the 1604s was shipped to the Pentagon to DASA (Defense Atomic Support Agency) a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
6502
The MOS Technology 6502 (typically pronounced "sixty-five-oh-two" or "six-five-oh-two") William Mensch and the moderator both pronounce the 6502 microprocessor as ''"sixty-five-oh-two"''. is an 8-bit microprocessor that was designed by a small team led by Chuck Peddle for MOS Technology. The design team had formerly worked at Motorola on the Motorola 6800 project; the 6502 is essentially a simplified, less expensive and faster version of that design. When it was introduced in 1975, the 6502 was the least expensive microprocessor on the market by a considerable margin. It initially sold for less than one-sixth the cost of competing designs from larger companies, such as the 6800 or Intel 8080. Its introduction caused rapid decreases in pricing across the entire processor market. Along with the Zilog Z80, it sparked a series of projects that resulted in the home computer revolution of the early 1980s. Home video game consoles and home computers of the 1970s through the early ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
8080
The Intel 8080 is Intel's second 8-bit microprocessor. Introduced in April 1974, the 8080 was an enhanced successor to the earlier Intel 8008 microprocessor, although without binary compatibility.'' Electronic News'' was a weekly trade newspaper. The same advertisement appeared in the May 2, 1974, issue of ''Electronics'' magazine. Originally intended for use in embedded systems such as calculators, cash registers, computer terminals, and industrial robots, its robust performance soon led to adoption in a broader range of systems, ultimately helping to launch the microcomputer industry. Several key design choices contributed to the 8080’s success. Its 40‑pin package simplified interfacing compared to the 8008’s 18‑pin design, enabling a more efficient data bus. The transition to NMOS technology provided faster transistor speeds than the 8008's PMOS while also simplifying interfacing by making it TTL compatible. An expanded instruction set and a full 16-bit address ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
16-bit
16-bit microcomputers are microcomputers that use 16-bit microprocessors. A 16-bit register can store 216 different values. The range of integer values that can be stored in 16 bits depends on the integer representation used. With the two most common representations, the range is 0 through 65,535 (216 − 1) for representation as an ( unsigned) binary number, and −32,768 (−1 × 215) through 32,767 (215 − 1) for representation as two's complement. Since 216 is 65,536, a processor with 16-bit memory addresses can directly access 64 KB (65,536 bytes) of byte-addressable memory. If a system uses segmentation with 16-bit segment offsets, more can be accessed. As of 2025, 16-bit microcontrollers cost well under a dollar (similar to close in price legacy 8-bit); the cheapest 16-bit microcontrollers cost less than other types including any 8-bit (and are more powerful, and easier to program generally), making 8-bit legacy microcontrollers not worth it for new applicatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bank Select Switch On Cromemco Memory Board
A bank is a financial institution that accepts deposits from the public and creates a demand deposit while simultaneously making loans. Lending activities can be directly performed by the bank or indirectly through capital markets. As banks play an important role in financial stability and the economy of a country, most jurisdictions exercise a high degree of regulation over banks. Most countries have institutionalized a system known as fractional-reserve banking, under which banks hold liquid assets equal to only a portion of their current liabilities. In addition to other regulations intended to ensure liquidity, banks are generally subject to minimum capital requirements based on an international set of capital standards, the Basel Accords. Banking in its modern sense evolved in the fourteenth century in the prosperous cities of Renaissance Italy but, in many ways, functioned as a continuation of ideas and concepts of credit and lending that had their roots in the ancien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory Bank
A memory bank is a logical unit of storage in electronics, which is hardware-dependent. In a computer, the memory bank may be determined by the memory controller along with physical organization of the hardware memory slots. In a typical synchronous dynamic random-access memory (SDRAM) or double data rate SDRAM (DDR SDRAM), a bank consists of multiple rows and columns of storage units, and is usually spread out across several chips. In a single read or write operation, only one bank is accessed, therefore the number of bits in a column or a row, per bank and per chip, equals the memory bus width in bits (single channel). The size of a bank is further determined by the number of bits in a column and a row, per chip, multiplied by the number of chips in a bank. Some computers have several identical memory banks of RAM, and use bank switching to switch between them. Harvard architecture computers have (at least) two very different banks of memory, one for program storage and anot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual Memory
In computing, virtual memory, or virtual storage, is a memory management technique that provides an "idealized abstraction of the storage resources that are actually available on a given machine" which "creates the illusion to users of a very large (main) memory". The computer's operating system, using a combination of hardware and software, maps memory addresses used by a program, called '' virtual addresses'', into ''physical addresses'' in computer memory. Main storage, as seen by a process or task, appears as a contiguous address space or collection of contiguous segments. The operating system manages virtual address spaces and the assignment of real memory to virtual memory. Address translation hardware in the CPU, often referred to as a memory management unit (MMU), automatically translates virtual addresses to physical addresses. Software within the operating system may extend these capabilities, utilizing, e.g., disk storage, to provide a virtual address space ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interrupt
In digital computers, an interrupt (sometimes referred to as a trap) is a request for the processor to ''interrupt'' currently executing code (when permitted), so that the event can be processed in a timely manner. If the request is accepted, the processor will suspend its current activities, save its state, and execute a function called an '' interrupt handler'' (or an ''interrupt service routine'', ISR) to deal with the event. This interruption is often temporary, allowing the software to resume normal activities after the interrupt handler finishes, although the interrupt could instead indicate a fatal error. Interrupts are commonly used by hardware devices to indicate electronic or physical state changes that require time-sensitive attention. Interrupts are also commonly used to implement computer multitasking and system calls, especially in real-time computing. Systems that use interrupts in these ways are said to be interrupt-driven. History Hardware interrupts wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory Location
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] |
Program Counter
The program counter (PC), commonly called the instruction pointer (IP) in Intel x86 and Itanium microprocessors, and sometimes called the instruction address register (IAR), the instruction counter, or just part of the instruction sequencer, is a processor register that indicates where a computer is in its program sequence. Usually, the PC is incremented after fetching an instruction, and holds the memory address of (" points to") the next instruction that would be executed. Processors usually fetch instructions sequentially from memory, but ''control transfer'' instructions change the sequence by placing a new value in the PC. These include branches (sometimes called jumps), subroutine calls, and returns. A transfer that is conditional on the truth of some assertion lets the computer follow a different sequence under different conditions. A branch provides that the next instruction is fetched from elsewhere in memory. A subroutine call not only branches but saves the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Port-mapped I/O
Memory-mapped I/O (MMIO) and port-mapped I/O (PMIO) are two complementary methods of performing input/output (I/O) between the central processing unit (CPU) and peripheral devices in a computer (often mediating access via chipset). An alternative approach is using dedicated I/O processors, commonly known as channels on mainframe computers, which execute their own instructions. Memory-mapped I/O uses the same address space to address both main memory and I/O devices. The memory and registers of the I/O devices are mapped to (associated with) address values, so a memory address may refer to either a portion of physical RAM or to memory and registers of the I/O device. Thus, the CPU instructions used to access the memory (e.g. ) can also be used for accessing devices. Each I/O device either monitors the CPU's address bus and responds to any CPU access of an address assigned to that device, connecting the system bus to the desired device's hardware register, or uses a dedicated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
