Instruct: Given a question, retrieve documents that can help answer the question.
Query: When was the first CPU developed?
The Intel 4004 is a 4-bit central processing unit (CPU) released by Intel Corporation in 1971. It was the first commercially available microprocessor by Intel,[2] and the first in a long line of Intel CPUs.
When a program runs on a single-CPU machine, the hardware performs the necessary bookkeeping to ensure that the program executes as if all memory operations were performed in the order specified by the programmer (program order), so memory barriers are not necessary. However, when the memory is shared with multiple devices, such as other CPUs in a multiprocessor system, or memory-mapped peripherals, out-of-order access may affect program behavior. For example, a second CPU may see memory changes made by the first CPU in a sequence which differs from program order.
Since the introduction of the first commercially available microprocessor, the Intel 4004 in 1970, and the first widely used microprocessor, the Intel 8080 in 1974, this class of CPUs has almost completely overtaken all other central processing unit implementation methods. Mainframe and minicomputer manufacturers of the time launched proprietary IC development programs to upgrade their older computer architectures, and eventually produced instruction set compatible microprocessors that were backward-compatible with their older hardware and software. Combined with the advent and eventual success of the ubiquitous personal computer, the term "CPU" is now applied almost exclusively to microprocessors. Several CPUs (denoted "cores") can be combined in a single processing chip.
Previous generations of CPUs were implemented as discrete components and numerous small integrated circuits (ICs) on one or more circuit boards. Microprocessors, on the other hand, are CPUs manufactured on a very small number of ICs; usually just one. The overall smaller CPU size, as a result of being implemented on a single die, means faster switching time because of physical factors like decreased gate parasitic capacitance. This has allowed synchronous microprocessors to have clock rates ranging from tens of megahertz to several gigahertz. Additionally, the ability to construct exceedingly small transistors on an IC has increased the complexity and number of transistors in a single CPU many fold. This widely observed trend is described by Moore's law, which had proven to be a fairly accurate predictor of the growth of CPU (and other IC) complexity until 2016.
Separate pages, each with a codename, were used to control the access to the I/O:
The Tube interface allowed Acorn to use BBC Micros with ARM CPUs as software development machines when creating the Acorn Archimedes. This resulted in the ARM development kit for the BBC Micro in 1986, priced at around £4000. From 2006 a kit with an ARM7TDMI CPU running at 64 MHz, with as much as 64 MB of RAM, was released for the BBC Micro and Master, using the Tube interface to upgrade the old 8-bit micros into 32-bit RISC machines. Among the software that operated on the Tube were an enhanced version of the "Elite" video game (see below) and a computer-aided design system that required a second 6502 CPU and a 3-dimensional joystick named a "Bitstik".
Several operating systems developed by Technical Systems Consultants (originally of West Lafayette Indiana, and later of Chapel Hill, North Carolina) used singly linked lists as file structures. A directory entry pointed to the first sector of a file, and succeeding portions of the file were located by traversing pointers. Systems using this technique included Flex (for the Motorola 6800 CPU), mini-Flex (same CPU), and Flex9 (for the Motorola 6809 CPU). A variant developed by TSC for and marketed by Smoke Signal Broadcasting in California, used doubly linked lists in the same manner.
One of the other prominent infrastructural developments during Dr. Juanito Acanto's term as a president, is the establishment of the university's own Television Channel, the "CPU TV Channel". The television channel, launched in 2001 under its former names, EXCEL TV, then was changed to CPU Alumni Channel in 2005, and to "CPU TV Channel", is the "first university–based cable TV channel in Asia", is one big leap in upholding the university's standard in quality education through the use of mass media. There were various new real properties also that is owned by the University when he was in his term as the President. The 24 hectares San Rafael Agricultural Land and the 14 hectare Guimaras Agricultural Land
Other research and auxiliary centers and extension programs of the University includes the CPU Research and Developmental Learning Center (Building), CPU Center for Local Governance and Indigenous Peoples Studies; CPU-World Bank Knowledge Development Center (CPU WB-KDC); CPU Appropriate Technology Center (CPU-APPROTECH); CPU Crop Research Laboratory; and the CPU – Social Science Research Institute.
VIA LongHaul is a CPU speed throttling and power saving technology developed by VIA Technologies. By executing specialized instructions, software can exercise fine control on the bus-to-core frequency ratio and CPU core voltage. When the system first boots, the ratio and voltage are set to hardware defaults. While the operating system runs, a "CPU driver" controls the throttling according to how much load is put on the CPU.
When the scheduler discovers a waking task, it will need to determine which logical CPU to run the wakening task on the non-unicore system. The scheduler favors most the idle hyperthreaded cores first on the same CPU that the task executed on, then the other idle core of a multicore CPU, then the other CPUs with the nearest cache locality on the same NUMA node, then those other CPUs outside the cache locality on the same NUMA node, then the other (remote) NUMA node and is ranked on a preference list. This special scan exists to minimize latency overhead resulting of migrating the task.
The total CPU time is the combination of the amount of time the CPU or CPUs spent performing some action for a program and the amount of time they spent performing system calls for the kernel on the program's behalf. When a program loops through an array, it is accumulating user CPU time. Conversely, when a program executes a system call such as codice_2 or codice_3, it is accumulating system CPU time.
In the history of computer and electronic chip development, there was a period when increases in CPU speed outpaced the improvements in memory access speed. The gap between the speed of CPUs and memory meant that the CPU would often be idle. CPUs were increasingly capable of running and executing larger amounts of instructions in a given time, but the time needed to access data from main memory prevented programs from fully benefiting from this capability. This issue motivated the creation of memory models with higher access rates in order to realize the potential of faster processors.
The machine can be configured to use only a single CPU at the Open Firmware prompt. There was also a developer utility to switch between single and dual CPU via a System Preferences preference pane. Using that API, a tool was developed to switch to single CPU on low load, enabling the low power mode and switching to dual CPU mode only when required. Soon after suggesting that hack to Apple, a new firmware was released, disabling the API for switching between single and dual CPU modes.
CPU time and CPU usage have two main uses. The first use is to quantify the overall busyness of the system. When the CPU usage is high, the user may experience lag. Such high CPU usage indicates insufficient processing power. Either the CPU needs to be upgraded, or the user experience reduced, for example, by switching to lower resolution graphics or reducing animations.
CPUs that have many execution units — such as a superscalar CPU, a VLIW CPU, or a reconfigurable computing CPU — typically have slower clock rates than a sequential CPU with one or two execution units when built from transistors that are just as fast. Nevertheless, CPUs with many execution units often complete real-world and benchmark tasks in less time than the supposedly faster high-clock-rate CPU.
The IBM Aptiva personal computer was introduced in September 1994 as the replacement for the IBM PS/1. The first Aptiva models were based on the Intel 80486 CPU with later models using the Pentium and AMD CPUs. All systems were developed in-house except for the later E series which was developed by Acer. The last system was withdrawn in May 2001 without direct replacement when IBM decided to exit the home market. Customers were directed to the IBM NetVista, which was more targeted to business desktops. Most Aptiva models included a modem and a standby/hibernation feature called "Rapid Resume".
OpenMP has been shown to be more efficient in performing coupled CFD-DEM calculations in parallel framework as compared to MPI by Amritkar et al. Recently, a multi-scale parallel strategy is developed. Generally, the simulation domain is divided into many sub-domains and each process calculates only one sub-domain using MPI passing boundary information; for each sub-domain, the CPUs are used to solve the fluid phase while the general purpose GPUs are used to solve the movement of particles. However, in this computation method CPUs and GPUs work in serial. That is, the CPUs are idle while the GPUs are calculating the solid particles, and the GPUs are idle when the CPUs are calculating the fluid phase. To further accelerate the computation, the CPU and GPU computing can be overlapped using the shared memory of a Linux system. Thus, the fluid phase and particles can be calculated at the same time.
In the 1960s, the development of electronic calculators, electronic clocks, the Apollo guidance computer, and Minuteman missile, helped make integrated circuits economical and practical. In the late 1960s, the first calculator and clock chips began to show that very small computers might be possible with large-scale integration (LSI). This culminated in the invention of the microprocessor, a single-chip CPU. The Intel 4004, released in 1971, was the first commercial microprocessor. The origins of the 4004 date back to the "Busicom Project", which began at Japanese calculator company Busicom in April 1968, when engineer Masatoshi Shima was tasked with designing a special-purpose LSI chipset, along with his supervisor Tadashi Tanba, for use in the Busicom 141-PF desktop calculator with integrated printer. His initial design consisted of seven LSI chips, including a three-chip CPU. His design included arithmetic units (adders), multiplier units, registers, read-only memory, and a macro-instruction set to control a decimal computer system. Busicom then wanted a general-purpose LSI chipset, for not only desktop calculators, but also other equipment such as a teller machine, cash register and billing machine. Shima thus began work on a general-purpose LSI chipset in late 1968. Sharp engineer Tadashi Sasaki, who also became involved with its development, conceived of a single-chip microprocessor in 1968, when he discussed the concept at a brainstorming meeting that was held in Japan. Sasaki attributes the basic invention to break the calculator chipset into four parts with ROM (4001), RAM (4002), shift registers (4003) and CPU (4004) to an unnamed woman, a software engineering researcher from Nara Women's College, who was present at the meeting. Sasaki then had his first meeting with Robert Noyce from Intel in 1968, and presented the woman's four-division chipset concept to Intel and Busicom.
The concept of CPU-bounding was developed during early computers, when data paths between computer components were simpler, and it was possible to visually see one component working while another was idle. Example components were CPU, tape drives, hard disks, card-readers, and printers. Computers that predominantly used peripherals were characterized as I/O bound. Establishing that a computer is frequently CPU-bound implies that upgrading the CPU or optimizing code will improve the overall computer performance.
This effort was not very successful because the ATA bus started out as a reduced-pin-count ISA bus. The requirement for software compatibility made ATA host bus adapters act like ISA bus devices without first party DMA. When a drive was ready for a transfer, it had to interrupt the CPU, wait for the CPU to ask the disk what command was ready to execute, respond with the command that it was ready to execute, wait for the CPU to program the host bus adapter's third-party DMA engine based on the result of that command, wait for the third party DMA engine to execute the command, and then had to interrupt the CPU again to notify it when the DMA engine finished the task so that the CPU could notify the thread that requested the task that the requested task was finished. Since responding to interrupts uses CPU time, CPU utilization rose quickly when ATA TCQ was enabled. Also, since interrupt service time can be unpredictable, there are times when the disk is ready to transfer data but is unable to do so because it must wait for a CPU to respond to the interrupt so that the CPU knows that it needs to program the third party DMA engine.
Many CPU hardware architectures provide far more flexibility than is exploited by the operating systems that they normally run. Proper use of complex CPU modes requires very close cooperation between the operating system and the CPU, and thus tends to tie the OS to the CPU architecture. When the OS and the CPU are specifically designed for each other, this is not a problem (although some hardware features may still be left unexploited), but when the OS is designed to be compatible with multiple, different CPU architectures, a large part of the CPU mode features may be ignored by the OS. For example, the reason Windows uses only two levels (ring 0 and ring 3) is that some hardware architectures that were supported in the past (such as PowerPC or MIPS) implemented only two privilege levels.
A direct consequence of the store buffer's existence is that when a CPU commits a write, that write is not immediately written in the cache. Therefore, whenever a CPU needs to read a cache line, it first has to scan its own store buffer for the existence of the same line, as there is a possibility that the same line was written by the same CPU before but hasn't yet been written in the cache (the preceding write is still waiting in the store buffer). Note that while a CPU can read its own previous writes in its store buffer, other CPUs "cannot see those writes" before they are flushed from the store buffer to the cache - a CPU cannot scan the store buffer of other CPUs.
Phase5 designed the PowerUP boards (Blizzard PPC and CyberStorm PPC) featuring both a 68k (a 68040 or 68060) and a PowerPC (603 or 604) CPU, which are able to run the two CPUs at the same time and share the system memory. The PowerPC CPU on PowerUP boards is usually used as a coprocessor for heavy computations; a powerful CPU is needed to run MAME for example, but even decoding JPEG pictures and MP3 audio was considered heavy computation at the time. It is also possible to ignore the 68k CPU and run Linux on the PPC via project Linux APUS, but a PowerPC-native AmigaOS promised by Amiga Technologies GmbH was not available when the PowerUP boards first appeared.
When CPU 1 issues a test-and-set instruction, the DPRAM first makes an "internal note" of this by storing the address of the memory location in a special place. If at this point, CPU 2 happens to issue a test-and-set instruction for the same memory location, the DPRAM first checks its "internal note", recognizes the situation, and issues a BUSY interrupt, which tells CPU 2 that it must wait and retry. This is an implementation of a busy waiting or spinlock using the interrupt mechanism. Since all this happens at hardware speeds, CPU 2's wait to get out of the spin-lock is very short.
The history of this CPU stems from the early 1970s, when the group of engineers in Zelenograd's Special Computing Center, led by D.I. Yuditsky, developed their first 16-bit minicomputer, called Elektronika NC-1. This machine, intended to directly compete with SM EVM series, was first released in 1973 and used the bit slice 4-bit 587 CPU, sometimes called the first Soviet microprocessor ever. Its descendants proved popular and were widely used in various control systems and telecom equipment. However, the bit-slice nature of their CPUs made these machines somewhat unwieldy, especially in military applications, and the need for a single-chip microprocessor was identified.
CPU Sim is a software development environment for the simulation of simple computers. It was developed by Dale Skrien to help students understand computer architectures. With this application the user is able to simulate new or existing simple CPUs. Users can create new virtual CPUs with custom machine language instructions, which are implemented by a sequence of micro instructions. CPU Sim allows the user to edit and run assembly language programs for the CPU being simulated.