Static random-access memory
Static random-access memory is a type of semiconductor memory that uses bistable latching circuitry to store each bit. SRAM exhibits data remanence, but it is still volatile in the conventional sense that data is lost when the memory is not powered; the term static differentiates SRAM from DRAM. SRAM is faster and more expensive than DRAM. Advantages: Simplicity – a refresh circuit is not needed Performance Reliability Low idle power consumptionDisadvantages: Price Density High operational power consumption The power consumption of SRAM varies depending on how it is accessed. On the other hand, static RAM used at a somewhat slower pace, such as in applications with moderately clocked microprocessors, draws little power and can have a nearly negligible power consumption when sitting idle – in the region of a few micro-watts. Several techniques have been proposed to manage power consumption of SRAM-based memory structures. General purpose products with asynchronous interface, such as the ubiquitous 28-pin 8K × 8 and 32K × 8 chips, as well as similar products up to 16 Mbit per chip with synchronous interface used for caches and other applications requiring burst transfers, up to 18 Mbit per chip integrated on chip as RAM or cache memory in micro-controllers as the primary caches in powerful microprocessors, such as the x86 family, many others to store the registers and parts of the state-machines used in some microprocessors on application specific ICs, or ASICs in Field Programmable Gate Array and Complex Programmable Logic Device Many categories of industrial and scientific subsystems, automotive electronics, similar, contain static RAM.
Some amount is embedded in all modern appliances, etc. that implement an electronic user interface. Several megabytes may be used in complex products such as digital cameras, cell phones, etc. SRAM in its dual-ported form is sometimes used for realtime digital signal processing circuits. SRAM is used in personal computers, workstations and peripheral equipment: CPU register files, internal CPU caches and external burst mode SRAM caches, hard disk buffers, router buffers, etc. LCD screens and printers normally employ static RAM to hold the image displayed. Static RAM was used for the main memory of some early personal computers such as the ZX80, TRS-80 Model 100 and Commodore VIC-20. Hobbyists home-built processor enthusiasts prefer SRAM due to the ease of interfacing, it is much easier to work with than DRAM as there are no refresh cycles and the address and data buses are directly accessible rather than multiplexed. In addition to buses and power connections, SRAM requires only three controls: Chip Enable, Write Enable and Output Enable.
In synchronous SRAM, Clock is included. Non-volatile SRAMs, or nvSRAMs, have standard SRAM functionality, but they save the data when the power supply is lost, ensuring preservation of critical information. NvSRAMs are used in a wide range of situations – networking and medical, among many others – where the preservation of data is critical and where batteries are impractical. PSRAMs have a DRAM storage core, combined with a self refresh circuit, they appear externally as a slower SRAM. They have a density/cost advantage over true SRAM, without the access complexity of DRAM. Bipolar junction transistor – fast but consumes a lot of power MOSFET – low power and common today Asynchronous – independent of clock frequency. Address, data in and other control signals are associated with the clock signalsIn 1990s, asynchronous SRAM used to be employed for fast access time. Asynchronous SRAM was used as main memory for small cache-less embedded processors used in everything from industrial electronics and measurement systems to hard disks and networking equipment, among many other applications.
Nowadays, synchronous SRAM is rather employed like Synchronous DRAM – DDR SDRAM memory is rather used than asynchronous DRAM. Synchronous memory interface is much faster as access time can be reduced by employing pipeline architecture. Furthermore, as DRAM is much cheaper than SRAM, SRAM is replaced by DRAM in the case when large volume of data is required. SRAM memory is however much faster for random access. Therefore, SRAM memory is used for CPU cache, small on-chip memory, FIFOs or other small buffers. Zero bus turnaround – the turnaround is the number of clock cycles it takes to change access to the SRAM from write to read and vice versa; the turnaround for ZBT SRAMs or the latency between read and write cycle is zero. SyncBurst – features synchronous burst write access to the SRAM to increase write operation to the SRAM DDR SRAM – Synchronous, single read/write port, double data rate I/O Quad Data Rate SRAM – Synchronous, separate read and write ports, quadruple data rate I/O Binary SRAM Ternary SRAM A typical SRAM cell is mad
The Macintosh Plus computer is the third model in the Macintosh line, introduced on January 16, 1986, two years after the original Macintosh and a little more than a year after the Macintosh 512K, with a price tag of US$2599. As an evolutionary improvement over the 512K, it shipped with 1 MB of RAM standard, expandable to 4 MB, an external SCSI peripheral bus, among smaller improvements, it had the same beige-colored case as the original Macintosh, but in 1987, the case color was changed to the long-lived, warm gray "Platinum" color. It is the earliest Macintosh model able to run System 7 OS. Bruce Webster of BYTE reported a rumor in December 1985: "Supposedly, Apple will be releasing a Big Mac by the time this column sees print: said Mac will come with 1 megabyte of RAM... the new 128K-byte ROM... and a double-sided disk drive, all in the standard Mac box". Introduced as the Macintosh Plus, it was the first Macintosh model to include a SCSI port, which launched the popularity of external SCSI devices for Macs, including hard disks, tape drives, CD-ROM drives, Zip Drives, monitors.
The SCSI implementation of the Plus was engineered shortly before the initial SCSI spec was finalized and, as such, is not 100% SCSI-compliant. SCSI ports remained standard equipment for all Macs until the introduction of the iMac in 1998, which replaced most of Apple's "legacy ports" with USB; the Macintosh Plus was the last classic Mac to have a phone cord-like port on the front of the unit for the keyboard, as well as the DE-9 connector for the mouse. The Mac Plus was the first Apple computer to utilize SIMM memory modules instead of single DIP DRAM chips. Four slots were provided and the computer shipped with four 256k SIMMs for 1MB total. By replacing them with 1MB SIMMs, it was possible to have 4MB of RAM. Although 30-pin SIMMs could support up to 16MB total RAM, the motherboard had only 22 address lines connected for 4MB, it has what was a new 3 1⁄2-inch double-sided 800 KB floppy drive, offering double the capacity of floppy disks for previous Macs, along with backward compatibility.
The then-new drive is controlled by the same IWM chip as in previous models, implementing variable speed GCR. The drive was still incompatible with PC drives; the 800 KB drive has two read/write heads, enabling it to use both sides of the floppy disk and thereby double storage capacity. Like the 400 KB drive before it, a companion Macintosh 800K External Drive was an available option. However, with the increased storage capacity combined with 2-4x the available RAM, the external drive was less of a necessity than it had been with the 128K and 512K; the Mac Plus has 128 KB of ROM on the motherboard, double the amount of ROM that's in previous Macs. For programmers, the fourth Inside Macintosh volume details how to use HFS and the rest of the Mac Plus's new system software; this new filing system allows it to use the first hard drive Apple developed for the 512K, the IWM floppy disk-based Hard Disk 20 and the then-new ROMs allow the Macintosh to use the drive as a startup disk for the first time.
The Plus still did not include provision for an internal hard drive and it would be over nine months before Apple would offer a SCSI drive replacement for the slow Hard Disk 20. It would be well over a year before Apple would offer the first internal hard disk drive in any Macintosh. A compact Mac, the Plus has a 9-inch 512×342 pixel monochrome display with a resolution of 72 PPI, identical to that of previous Macintosh models. Unlike earlier Macs, the Mac Plus's keyboard includes a numeric keypad and directional arrow keys and, as with previous Macs, it has a one-button mouse and no fan, making it quiet in operation; the lack of a cooling fan in the Mac Plus led to frequent problems with overheating and hardware malfunctions. The applications MacPaint and MacWrite were bundled with the Mac Plus. After August 1987, HyperCard and MultiFinder were bundled. Third-party software applications available included MacDraw, Microsoft Word and PowerPoint, as well as Aldus's PageMaker. Microsoft Excel and PowerPoint were developed and released first for the Macintosh, Microsoft Word 1 for Macintosh was the first time a GUI version of that software was introduced on any personal computer platform.
For a time, the exclusive availability of Excel and PageMaker on the Macintosh were noticeable drivers of sales for the platform. The case design is identical to the original Macintosh, it debuted in beige and was labeled Macintosh Plus on the front, but Macintosh Plus 1 MB on the back, to denote the 1 MB RAM configuration with which it shipped. In January 1987 it transitioned to Apple's long-lived platinum-gray color with the rest of the Apple product line, the keyboard's keycaps changed from brown to gray. In January 1988, with reduced RAM prices, Apple began shipping 2- and 4- MB configurations and rebranded it as "Macintosh Plus." Among other design changes, it included the same trademarked inlaid Apple logo and recessed port icons as the Apple IIc and IIGS before it, but it retained the original design. An upgrade kit was offered for the earlier Macintosh 128K and Macintosh 512K/enhanced, which includes a new motherboard, floppy disk drive and rear case; the owner retained the front case, monitor, a
The IBM PCjr is a home computer, produced and marketed by IBM from March 1984 to May 1985. The PCjr was positioned as a complement to the successful IBM Personal Computer, competing with other home computers such as the Apple II series and the Commodore 64, it retains the IBM PC's 8088 CPU and BIOS interface, but provides enhanced graphics and sound capabilities over the original IBM PC, ROM cartridge slots, joystick ports, an infrared wireless keyboard. The PCjr supports expansion via "sidecar" modules. New software such as King's Quest. Despite widespread anticipation, the PCjr's launch was unsuccessful. IBM's inexperience with the consumer market led to unclear positioning, with analysts believing that IBM was unsuccessful at justifying the PCjr's higher cost in comparison to competitors such as the Commodore 64 and Apple II, it is only IBM compatible, so compatibility with existing PC software such as the killer app Lotus 1-2-3 was not guaranteed. The PCjr's chiclet keyboard was criticized for its poor quality, with critics stating that it was unsuitable for extended use such as word processing.
The PCjr's expandability was limited, it was offered with up to 128 KB of RAM only, insufficient for many IBM PC programs. The New York Times stated that the PCjr was incapable of "serious business computing". Consumers were more interested in Apple's newly-unveiled Macintosh than the PCjr. Apple cut the price of the IIe and introduced the IIc as a direct competitor, with advertising promoting its compatibility with existing Apple II software. In 1984, IBM offered free replacement keyboards with a more traditional design, a new 512 KB RAM upgrade. A large advertising campaign promoted the PCjr's compatibility with "over 1000" of the most popular IBM PC applications, new discounted pricing and other bundle offers. By January 1985, when the discounts ended, IBM had sold 250,000 PCjr computers, with 200,000 in the fourth quarter of 1984 alone. Unable to sell the computer without discounts, IBM discontinued the PCjr in March 1985, IBM would not produce a home-oriented computer until the PS/1 in 1990.
Time described the PCjr as "one of the biggest flops in the history of computing", with critics comparing it to the Ford Edsel and New Coke. The Tandy Corporation's clone of the PCjr, the Tandy 1000, was a more successful product, due to its cheaper cost, easier expandability, wider PC compatibility than the PCjr; the graphics and sound specifications of the PCjr became more synonymous with Tandy as a result, leading to computers and software supporting them being referred to as "Tandy compatible". Announced November 1, 1983, first shipped in late January 1984, the PCjr—nicknamed "Peanut" before its debut—came in two models: the 4860-004, with 64 KB of memory, priced at US$669, it was manufactured for IBM in Tennessee by Teledyne. The PCjr promised a high degree of compatibility with the IBM PC, a popular business computer, in addition to offering built-in color graphics and 3 voice sound, better than the standard PC-speaker sound and color graphics of the standard IBM PC and compatibles of the day.
The PCjr is the first PC compatible machine, expressly designed to support page flipping for graphics operations. Since the PCjr uses system RAM to store video content, the location of this storage area can be changed, it can perform flicker-free animation and other effects that are difficult or impossible to produce on contemporary PC clones. Unlike the standard IBM PC, the PCjr has onboard video hardware, it is an improved subset of the CGA standard. The four CGA video modes are supported in addition to three new graphics modes; the 80x25 text mode, 320x200x16, 640x200x4 modes are referred to in IBM's documentation as "the high bandwidth modes". The PCjr has a composite video out and can support artifact colors on a TV or composite monitor much like the CGA cards, although the colors are different; the PCjr has palette registers which allow the colors to be redefined for any of the available 16--this feature was retained in EGA and VGA cards. When the BIOS is used to set a video mode, it always sets up the PCjr palette table to emulate the CGA color palette for that mode.
Programs written to use PCjr graphics can subsequently reprogram the palette table to use any colors desired. Palette changes must be made during horizontal or vertical blanking periods of a video frame in order to avoid corrupting the display. However, the provision of a vertical retrace interrupt simplifies this and makes seamless page-flipping much easier. Although standard PC video cards had a flag to indicate that the vertical retrace was in progress, the PCjr added for the first time the ability to generate raster or VBLANK interrupts on IRQ 5; this allowed the use of mixed video modes. The PCjr video subsystem has a little-known graphics blink feature, which toggles the palette between the first and second groups of eight palette registers at the same rate used for the text blink feature, a palette bit-masking feature that could be used to switch between palette subsets without reprogramming palette registers, by forcing one or more bits of each pixel value to zero before the value is used to look up the color in the pale
Apple Computer 1 known as the Apple I, or Apple-1, is a desktop computer released by the Apple Computer Company in 1976. It was hand-built by Steve Wozniak. Wozniak's friend Steve Jobs had the idea of selling the computer; the Apple I was Apple's first product, to finance its creation, Jobs sold his only motorized means of transportation, a VW Microbus, for a few hundred dollars, Steve Wozniak sold his HP-65 calculator for $500. It was demonstrated in July 1976 at the Homebrew Computer Club in California. Production was discontinued on September 30, 1977, after the June 10, 1977 introduction of its successor, the Apple II, which Byte magazine referred to as part of the "1977 Trinity" of personal computing. On March 5, 1975, Steve Wozniak attended the first meeting of the Homebrew Computer Club in Gordon French's garage, he was so inspired that he set to work on what would become the Apple I computer. After building it for himself and showing it at the Club, he and Steve Jobs gave out schematics for the computer to interested club members and helped some of them build and test out copies.
Steve Jobs suggested that they design and sell a single etched and silkscreened circuit board—just the bare board, with no electronic parts—that people could use to build the computers. Wozniak calculated that having the board design laid out would cost $1,000 and manufacturing would cost another $20 per board. To fund this small venture—their first company—Jobs sold his van and Wozniak sold his HP-65 calculator. Soon after, Steve Jobs arranged to sell "something like 50" built computers to the Byte Shop at $500 each. To fulfill the $25,000 order, they obtained $20,000 in parts at 30 days net and delivered the finished product in 10 days; the Apple I went on sale in July 1976 at a price of US$666.66, because Wozniak "liked repeating digits" and because of a one-third markup on the $500 wholesale price. The first unit produced was used in a high school math class, donated to Liza Loop's public-access computer center. About 200 units were produced, all but 25 were sold within nine or ten months.
The Apple I's built-in computer terminal circuitry was distinctive. All one needed was a television set. Competing machines such as the Altair 8800 were programmed with front-mounted toggle switches and used indicator lights for output, had to be extended with separate hardware to allow connection to a computer terminal or a teletypewriter machine; this made the Apple I an innovative machine for its day. In April 1977, the price was dropped to $475, it continued to be sold through August 1977, despite the introduction of the Apple II in April 1977, which began shipping in June of that year. In October 1977, the Apple I was discontinued and removed from Apple's price list; as Wozniak was the only person who could answer most customer support questions about the computer, the company offered Apple I owners discounts and trade-ins for Apple IIs to persuade them to return their computers. These recovered boards were destroyed by Apple, contributing to their rarity today; as of 2013, sixty-three Apple I computers have been confirmed to exist.
Only six have been verified to be in working condition. The Apple-1 Registry lists every known Apple I computer; this registry serves an additional purpose by including a list of all auctions since 2000. An Apple I sold for US$50,000 at auction in 1999. In 2008, the website Vintage Computing and Gaming reported that Apple I owner Rick Conte was looking to sell his unit and was "expecting a price in excess of $15,000 U. S." The site reported Conte had donated the unit to the Maine Personal Computer Museum in 2009. A unit was sold in September 2009 for $17,480 on eBay. A unit belonging to early Apple Computer engineers Dick and Cliff Huston was sold on March 23, 2010, for $42,766 on eBay. In November 2010, an Apple I sold for £133,250 at Christie's auction house in London; the high price was due to the rare documents and packaging offered in the sale in addition to the computer, including the original packaging, a typed and signed letter from Jobs, the original invoice showing "Steven" as the salesman.
The computer was brought to Polytechnic University of Turin where it was fixed and used to run the BASIC programming language. On June 15, 2012, a working Apple I was sold at auction by Sotheby's for a then-record $374,500, more than double the expected price; this unit is on display at the Nexon Computer Museum in South Korea. In October 2012, a non-working Apple I from the estate of former Apple Computer employee Joe Copson was put up for auction by Christie's, but found no bidder, willing to pay the starting price of US$80,000. Copson's board had been listed on eBay in December 2011, with a starting bid of $170,000 and failed to sell. Following the Christie's auction, the board was restored to working condition by computer historian Corey Cohen. Copson's Apple I was once again listed on eBay, where it sold for US$236,100.03 on April 23, 2015. On November 24, 2012, a working Apple I was sold at auction by Auction Team Breker for €400,000. On May 25, 2013, a functioning 1976 model was sold for a then-record €516,000 in Cologne.
Auction Team Breker said "an unnamed Asian
The Apple IIc, the fourth model in the Apple II series of personal computers, is Apple Computer’s first endeavor to produce a portable computer. The result was a 7.5 lb notebook-sized version of the Apple II that could be transported from place to place. The c in the name stood for compact, referring to the fact it was a complete Apple II computer setup squeezed into a small notebook-sized housing. While sporting a built-in floppy drive and new rear peripheral expansion ports integrated onto the main logic board, it lacks the internal expansion slots and direct motherboard access of earlier Apple II models, making it a closed system like the Macintosh. However, the intended direction for this model — a more appliance-like machine, ready to use out of the box, requiring no technical know-how or experience to hook up and therefore attractive to first-time users; the Apple IIc was released on April 1984, during an Apple-held event called Apple II Forever. With that motto, Apple proclaimed the new machine was proof of the company's long-term commitment to the Apple II series and its users, despite the recent introduction of the Macintosh.
The IIc was seen as the company's response to the new IBM PCjr, Apple hoped to sell 400,000 by the end of 1984. While an Apple IIe computer in a smaller case, it was not a successor, but rather a portable version to complement it. One Apple II machine would be sold for users who required the expandability of slots, another for those wanting the simplicity of a plug and play machine with portability in mind; the machine introduced Apple’s Snow White design language, notable for its case styling and a modern look designed by Hartmut Esslinger which became the standard for Apple equipment and computers for nearly a decade. The Apple IIc introduced a unique off-white coloring known as “Fog,” chosen to enhance the Snow White design style; the IIc and some peripherals were the only Apple products. While light-weight and compact in design, the Apple IIc was not a true portable in design as it lacked a built-in battery and display. Codenames for the machine while under development included: Lollie, ET, Teddy, VLC, IIb, IIp.
Technically the Apple IIc was an Apple IIe in a smaller case, more portable and easier to use but less expandable. The IIc used the CMOS-based 65C02 microprocessor which added 27 new instructions to the 6502, but was incompatible with programs that used deprecated illegal opcodes of the 6502; the new ROM firmware allowed Applesoft BASIC to recognize lowercase characters and work better with an 80-column display, fixed several bugs from the IIe ROM. In terms of video, the text display added 32 unique character symbols called "MouseText" which, when placed side by side, could display simple icons and menus to create a graphical user interface out of text, similar in concept to IBM code page 437 or PETSCII's box-drawing characters. A year the Apple IIe would benefit from these improvements in the form of a four-chip upgrade called the Enhanced IIe; the equivalent of five expansion cards were built-in and integrated into the Apple IIc motherboard: An Extended 80 Column Card, two Apple Super Serial Cards, a Mouse Card, a disk floppy drive controller card.
This meant the Apple IIc had 128 KB RAM, 80-column text, Double-Hi-Resolution graphics built-in and available right out of the box, unlike its older sibling, the Apple IIe. It meant less of a need for slots, as the most popular peripheral add-on cards were built-in, ready for devices to be plugged into the rear ports of the machine; the built-in cards were mapped to phantom slots so software from slot-based Apple II models would know where to find them. The entire Apple Disk II Card, used for controlling floppy drives, had been shrunk down into a single chip called the “IWM” which stood for Integrated Woz Machine. In the rear of the machine were its expansion ports for providing access to its built-in cards; the standard DE-9 joystick connector doubled as a mouse interface, compatible with the same mice used by the Lisa and early Macintosh computers. Two serial ports were provided to support a printer and modem, a floppy port connector supported a single external 5.25-inch drive. A Video Expansion port provided rudimentary signals for add-on adapters but, could not directly generate a video signal.
A port connector tied into an internal 12 V power converter for attaching batteries. The same composite video port found on earlier Apple II models remained present; the Apple IIc had a built-in 5.25-inch floppy drive along the right side of the case—the first Apple II model to include such a feature. Along the left side of the case was a dial to control the volume of the internal speaker, along with a 1⁄8-inch monaural audio jack for headphones or an external speaker. A fold-out carrying handle doubled as a way to prop up the back end of the machine to angle the keyboard for typing, if desired; the keyboard layout mirrored that of the Apple IIe. Two toggle switches were located in the same area: an “80/40”-column switch for software
KansasFest is an annual event for Apple II computer enthusiasts. Held every July at Rockhurst University in Kansas City, KansasFest lasts five days and features presentations from Apple II experts and pioneers, as well as games, fun events, after-hours hallway chatter, late-night runs out to movies or restaurants, more. A number of important new products have been released at KansasFest or developed through collaborations between individuals who would not have gotten together; some of the most notable have been the introduction of the LANceGS Ethernet Card, the Marinetti TCP/IP stack for the Apple IIGS. The dates of the 31st annual KansasFest are July 15–21, 2019. Vendor fairs were part of the earliest days of the microcomputer revolution; the Apple II had its debut at the first West Coast Computer Faire in April, 1977. The popularity of this faire spawned other similar computer events elsewhere in the country. In the early 1980s, some of these vendor fairs became more computer-specific. For the Apple II computer, it began with AppleFest'81, sponsored by the Apple group in the Boston Computer Society.
These festivals spread to be held in various places in the country, Apple Computer became involved to the point of sending executives to give keynote addresses, holding sessions for developers. After the introduction of the Apple III, Lisa and Macintosh computers, Apple II users and developers were feeling isolated and ignored by Apple Computer. Tom Weishaar had started a newsletter, Open-Apple about the Apple II, in it he provided information about the computer, how to use it, product reviews, more. With time, he created a company named Resource Central to oversee the newsletter and other products available to sell to subscribers. Frustrated by Apple's diminishing emphasis on the Apple II, Weishaar planned a developer's conference that would focus on the Apple II and Apple IIGS; the first event was held in July 1989, was called the A2-Central Developer Conference, billed as a chance to "meet the people who will make the Apple II's future". The conference brought together programmers, hardware developers, Apple sent out a number of members of its Apple II group to participate in the meeting.
What made it different from many similar meetings was the way in which the accommodations were handled. Resource Central, based in Overland Park, arranged for the meeting and housing for many of the attendees at Avila College, a Catholic institution located in Kansas City, not far from Overland Park. One of the unanticipated effects of this arrangement was that the college dorm environment encouraged interaction between participants in a way that would not have happened in a hotel. Nearly all who made the trip to the conference found it a significant and positive experience, were more than ready to do it again the following year. Resource Central continued to host these annual summer meetings, changing the name to the A2-Central Summer Conference. By the third meeting in 1991, its attendees had informally given it the name, "KansasFest", a portmanteau of "Kansas" and the "AppleFest" events held elsewhere in the country. Resource Central's sponsorship and management lasted through six KansasFest July conferences, the last being held in 1994.
Due to Apple Computer's decision to discontinue production of the Apple IIGS in late 1992 and the Apple IIe in late 1993, the rise of the Macintosh and of computers running MS-DOS, the Apple II market began to diminish. At Resource Central, finances became a problem during 1994, a crisis hit the company at the start of 1995. Declining renewals of the A2-Central newsletter and other products the company sold could no longer sustain the business, it was necessary to shut down in February of that year; this put into doubt the prospects of continuing the annual KansasFest meeting. To rescue it, a committee was formed amongst previous attendees, coordinated online via GEnie. By spring of 1995 they had secured Avila for a two-day meeting, had enough who had committed to come that KansasFest 1995 could be held. From 1995 through 2004, KansasFest continued to be held at Avila. In the earlier years, it served as an annual rallying point for the Apple II community, as it found itself in a world shrinking in resources that would support it.
Like Resource Central, other businesses that dealt with the Apple II found it difficult to survive. The online homes for direct-dial Apple II access were having problems with either Y2K or transition to the World Wide Web, were phasing out their text-based access. Although the annual KansasFest event was coordinated on those online services, the physical meeting provided a recurring connection point. By the time its second decade began in 1999, KansasFest was becoming as much about preservation of the past as it was about advancing the Apple II platform; the conference began to have sessions covering computing on the Macintosh and Palm computers. Attendees were not programmers or developers, but were those who enjoyed retrocomputing or had a nostalgic connection with the Apple II, it was a venue for demonstration of new uses for the Apple II that had never been considered. For example, Michael Mahon showed off his AppleCrate parallel processing Apple II in 2007, with a number of Apple IIe boards connected together, updated to a seventeen board system by the following year.
A programmer, David Schmenk wrote a first-person maze game in 2007, "Escape From The Homebrew Computer Club" using 16-color lo-res graphics, something that could have been run on an Apple II in 1977 if anyo
In electronic systems and computing, firmware is a specific class of computer software that provides the low-level control for the device's specific hardware. Firmware can either provide a standardized operating environment for the device's more complex software, or, for less complex devices, act as the device's complete operating system, performing all control and data manipulation functions. Typical examples of devices containing firmware are embedded systems, consumer appliances, computer peripherals, others. All electronic devices beyond the simplest contain some firmware. Firmware is held in non-volatile memory devices such as EPROM, or flash memory. Changing the firmware of a device was or never done during its lifetime in the past but is nowadays a common procedure. Common reasons for updating firmware include adding features to the device; this may require ROM integrated circuits to be physically replaced or flash memory to be reprogrammed through a special procedure. Firmware such as the ROM BIOS of a personal computer may contain only elementary basic functions of a device and may only provide services to higher-level software.
Firmware such as the program of an embedded system may be the only program that will run on the system and provide all of its functions. Before the inclusion of integrated circuits, other firmware devices included a discrete semiconductor diode matrix; the Apollo guidance computer had firmware consisting of a specially manufactured core memory plane, called "core rope memory", where data was stored by physically threading wires through or around the core storing each data bit. Ascher Opler coined the term "firmware" in a 1967 Datamation article, it meant the contents of a writable control store, containing microcode that defined and implemented the computer's instruction set, that could be reloaded to specialize or modify the instructions that the central processing unit could execute. As used, firmware contrasted with hardware and software, it was not composed of CPU machine instructions, but of lower-level microcode involved in the implementation of machine instructions. It existed on the boundary between software.
Over time, popular usage extended the word "firmware" to denote any computer program, linked to hardware, including processor machine instructions for BIOS, bootstrap loaders, or the control systems for simple electronic devices such as a microwave oven, remote control, or computer peripheral. In some respects, the various firmware components are as important as the operating system in a working computer. However, unlike most modern operating systems, firmware has a well-evolved automatic mechanism of updating itself to fix any functionality issues detected after shipping the unit; the BIOS may be "manually" updated by a user. In contrast, firmware in storage devices gets updated when flash storage is used for the firmware. Most computer peripherals are themselves special-purpose computers. Devices such as printers, cameras, USB flash drives have internally stored firmware; some low-cost peripherals no longer contain non-volatile memory for firmware, instead rely on the host system to transfer the device control program from a disk file or CD.
As of 2010, most portable music players support firmware upgrades. Some companies use firmware updates to add new playable file formats. Other features that may change with firmware updates include the GUI or the battery life. Most mobile phones have a Firmware Over The Air firmware upgrade capability for much the same reasons. Since 1996, most automobiles have employed an on-board computer and various sensors to detect mechanical problems; as of 2010, modern vehicles employ computer-controlled anti-lock braking systems and computer-operated transmission control units. The driver can get in-dash information while driving in this manner, such as real-time fuel economy and tire pressure readings. Local dealers can update most vehicle firmware. Examples of firmware include: In consumer products: Timing and control systems for washing machines Controlling sound and video attributes, as well as the channel list, in modern TVs EPROM chips used in the Eventide H-3000 series of digital music processors In computers: The BIOS found in IBM-compatible personal computers The EFI-compliant firmware used on Itanium systems, Intel-based computers from Apple, many Intel desktop computer motherboards Open Firmware, used in SPARC-based computers from Sun Microsystems and Oracle Corporation, PowerPC-based computers from Apple, computers from Genesi ARCS, used in computers from Silicon Graphics Kickstart, used in the Amiga line of computers RTAS, used in computers from IBM The Common Firmware Environment In routers and firewalls: LibreCMC – a 100% free software router distribution based on the Linux-libre kern