The TI-82 is a graphing calculator made by Texas Instruments. The TI-82 was designed in 1993 as a stripped down, more user friendly version of the TI-85, as a replacement for the TI-81, it was the direct predecessor of the TI-83. It shares with the TI-85 a 6 MHz Zilog Z80 microprocessor. Like the TI-81, the TI-82 features a 96x64 pixel display, the core feature set of the TI-81 with many new features; the TI-82 is powered by the same processor that powered its cousin, the TI-85, a 6 MHz Zilog Z80 microprocessor. This was an improvement over the TI-81's 2 MHz Z80 processor. In addition, the available RAM was increased more than tenfold – from 2400 bytes to 28734 bytes; some of the more notable improvements of the TI-82 over the TI-81 include the following: the addition of a link port to enable programs and other data to be transferred between two calculators or between a calculator and a computer. The last of these provided a significant boost in interest in the programmability of the calculator, as the use of assembly language enabled more performance and flexibility with the programs able to be used on the calculator.
Carried over from the TI-81 is the TI-82's power source – four AAA batteries and one CR1616 or CR1620 lithium backup battery. The TI-82 was redesigned twice, first in 1999 and again in 2001; the 1999 redesign introduced a design similar to the TI-73, TI-83 Plus, the TI-89. It introduced a more contoured body and eliminated the sloped screen, common on TI graphing calculators since the TI-81; the 2001 redesign introduced a different shape to the calculator, eliminated the glossy screen border, reduced cost by streamlining the printed circuit board to four units. An enhanced version of the TI-82, the TI-82 STATS, was first released in 2002 in Europe. There are several improvements, most notably the statistical features. In addition, it featured numerical differentiation and integration, together with complex numbers, financial functions and other improvements. In specification terms, it is identical to the TI-83. CPU Zilog Z80 CPU, 6 MHz RAM 32 KB, 28734 bytes user-accessible Display Text: 8 Rows × 16 characters Graphics: 96×64 pixels, monochrome I/O Link port Power 4 AAA batteries plus 1 CR1616/CR1620 lithium battery for backup Integrated programming languages TI-BASIC, Assembly Comparison of Texas Instruments graphing calculators Texas Instruments press release March 30, 1993 ticalc.org – The largest archive of TI programs available
A type-in program or type-in listing is a listing of source code printed in a computer magazine or book, meant to be entered on the computer's keyboard by the reader and saved to cassette or disk. Type-in programs were common in the early home computer era from the late 1970s through the 1980s when the RAM of 8-bit systems was measured in kilobytes and most computer owners did not have access to networks such a bulletin board systems. A computer magazine could contain multiple games or other programs for a fraction of the cost of commercial software, but the user had to spend up to several hours typing each one in. Magazines such as Softalk, Compute!, ANALOG Computing, Ahoy! Dedicated much of each issue to type-in programs. All listings were in a system-specific BASIC dialect or machine language. Machine language programs were long lists of decimal or hexadecimal numbers in the form of DATA statements in BASIC, accompanied by more readable assembly language source code which did not need to be entered.
Most magazines had error checking software. Type-in programs did not carry over to 16-bit computers such as the Amiga and Atari ST in a significant way, it became common to include a 3½-inch floppy disk with each issue of a magazine. A reader would take a printed copy of the program listing, such as from a magazine or book, sit down at a computer, manually enter the lines of code. Computers of this era automatically booted into a programming environment – the commands to load and run a prepackaged program were programming commands executed in direct mode. After typing the program in, the user would be able to run it and to save it to disk or cassette for future use. Users were cautioned to save the program before running it, as errors could result in a crash requiring a reboot, which would render the program irretrievable unless it had been saved; the simple program displayed above is a trivial example - many type-ins were functional games or application software, sometimes rivaling commercial packages.
Type-ins were written in BASIC or a combination of a BASIC loader and machine language. In the latter case, the opcodes and operands of the machine language part were simply given as DATA statements within the BASIC program, were loaded using a POKE loop, since few users had access to an assembler. In some cases, a special program for entering machine language numerically was provided. Programs with a machine language component sometimes included assembly language listings for users who had assemblers and who were interested in the internal workings of the program; the downside of type-ins was labor. The work required to enter a medium-sized type-in was on the order of hours. If the resulting program turned out not to be to the user's taste, it was quite possible that the user spent more time keying in the program than using it. Additionally, type-ins were error-prone, both for the magazines; this was true of the machine language parts of BASIC programs, which were nothing but line after line of DATA statements.
In some cases where the version of ASCII used on the type of computer the program was published for included printable characters for each value from 0–255, the code could have been printed using strings that contained the glyphs that the values mapped to, or a mnemonic such as instructing the user which keys to press. While a BASIC program would stop with an error at an incorrect statement, the machine language parts of a program could fail in untraceable ways; this made the correct entry of programs difficult. To counter the difficulty of keying a type-in, the MIKBUG machine code monitor for the Motorola 6800 of the late 1970s incorporated a checksum into its hexadecimal program listings; some magazines developed checksum programs of their own. There were many different styles of checksum program depending on the type of program being entered and on the complexity of the checksummer. Checksummers were proprietary and were printed in every issue of the magazine; the most basic distinction was whether the checksummer was run only once, when the program had been keyed in, or whether it was used interactively.
The former type either read it directly from memory. The checksum program would print a checksum for each line of code; the magazine would print the correct checksums adjacent to the listing, the user would compare the two to catch errors. More advanced checksum programs were used interactively, they would take a line of code as it was entered and produce a checksum which could be compared to the printed listing. Users, had to enter the checksum programs themselves correctly. For example, Compute! and Compute!'s Gazette printed the BASIC listings for "The Automatic Proofreader" and "MLX" in each issue that carried type-in programs in these formats. Once the user had typed in "The Automatic Proofreader" he had bootstrapped his way to verifying "MLX" and other programs. Beyond the manual labor of type-ins, it was not uncommon for certain magazines to print poor quality listings, presenting the reader with nearly illegible characters; this was troublesome in listings which contained graphical characters representing control codes, used for e.g. cursor movements.
An adapter or adaptor is a device that converts attributes of one device or system to those of an otherwise incompatible device or system. Some modify power or signal attributes, while others adapt the physical form of one connector to another. Many countries with ties to Europe use 230-volt, 50 Hz AC mains electricity, using a variety of power plugs and sockets. Difficulty arises. A passive electric power adapter, sometimes called a travel plug or travel adapter, allows using a plug from one region with a foreign socket; as other countries supply 120-volt, 60 Hz AC, using a travel adapter in a country with a different supply poses a safety hazard if the connected device does not support both input voltages. An AC-to-DC power supply adapts electricity from household mains voltage to low-voltage DC suitable for powering consumer electronics. Small, detached power supplies for consumer electronics are called AC adapters, or variously power bricks, wall warts, or chargers. A host controller connects a computer to a peripheral device, such as a storage device, network, or human interface device.
As a host controller can be viewed as bridging the protocols used on the buses between peripheral and computer, internally to the computer, it is called a host bus adapter. Specific types may be called adapters: a network interface controller may be called a network adapter, a graphics card a display adapter. Adapters allow connecting a peripheral device with one plug to a different jack on the computer, they are used to connect modern devices to a legacy port on an old system, or legacy devices to a modern port. Such adapters may be passive, or contain active circuitry. A common type is a USB adapter. One kind of serial port adapter enables connections between 25-contact and nine-contact connectors, but does not affect electrical power- and signalling-related attributes. High pressure gases are connected from a storage container to the device using the gas via a pressure hose that has standard connectors. To allow different standards to inter-operate, adapters are used. AC power plugs and sockets Dongle Repurposing
Thermal printing is a digital printing process which produces a printed image by selectively heating coated thermochromic paper, or thermal paper as it is known, when the paper passes over the thermal print head. The coating turns black in the areas where it is heated. Two-colour direct thermal printers can print both black and an additional colour by applying heat at two different temperatures. Thermal transfer printing is a different method that uses a heat-sensitive ribbon instead of heat-sensitive paper, but uses similar thermal print heads. A thermal printer comprises; the printer sends an electric current to the heating elements of the thermal head, which generate heat. The heat activates the thermo-sensitive coloring layer of the thermosensitive paper, which changes color where heated; such a printing mechanism is known as direct system. The heating elements are arranged as a line of small spaced dots; the paper is impregnated with a solid-state mixture of a suitable matrix. When the matrix is heated above its melting point, the dye reacts with the acid, shifts to its colored form, the changed form is conserved in metastable state when the matrix solidifies back enough.
Thermal printers print more and faster than impact dot matrix printers. They are smaller and consume less power, making them ideal for portable and retail applications, its efficiency can be utilized in retail sectors. Roll-based printers can be refilled. Commercial applications of thermal printers include filling station pumps, information kiosks, point of sale systems, voucher printers in slot machines, print on demand labels for shipping and products, for recording live rhythm strips on hospital cardiac monitors. Many popular microcomputer systems from the late 1970s and early 1980s had first-party and aftermarket thermal printers available for them - such as the Atari 822 printer for the Atari 8-bit systems, the Apple Silentype for the Apple II and the Alphacom 32 for the Sinclair ZX Spectrum and ZX81, they used unusually-sized supplies and were used for making permanent records of information in the computer, rather than for correspondence. Through the 1990s many fax machines used thermal printing technology.
Toward the beginning of the 21st century, thermal wax transfer and inkjet printing technology supplanted thermal printing technology in fax machines, allowing printing on plain paper. Thermal Receipt Printers are efficient and quick, its efficiency can be utilized in retail sectors. Thermal printers are still used in seafloor exploration and engineering geology due to their portability and ability to create continuous reels or sheets. Thermal printers found in offshore applications are used to print realtime records of side scan sonar and sub-seafloor seismic imagery. In data processing, thermal printers are sometimes used to create hard copies of continuous seismic or hydrographic records stored in digital SEG Y or XTF form; the Game Boy Printer, released in 1998, was a small thermal printer used to print out certain elements from some Game Boy games. Early formulations of the thermo-sensitive coating used in thermal paper were sensitive to incidental heat, friction and water. Thermal coating formulations are far more stable.
In many hospitals in the United Kingdom, many common ultrasound sonogram devices output the results of the scan onto thermal paper. This can cause problems if the parents wish to preserve the image by laminating it, as the heat of most laminators will darken the entire page—this can be tested for beforehand on an unimportant thermal print. An option is to laminate a permanent ink duplicate of the image. Reports began surfacing of studies in the 2000s finding the oestrogen-related chemical bisphenol A mixed in with thermal papers. While the health concerns are uncertain, various health and science oriented political pressure organizations such as the Environmental Working Group have pressed for these versions to be pulled from market. Barcode printer Thermal transfer printing Computer printing Daisy wheel printing Dye-sublimation printer Line matrix printer Line printer Label printer Label printer applicator Thermographic printing Game Boy Printer
Computer data storage
Computer data storage called storage or memory, is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers; the central processing unit of a computer is. In practice all computers use a storage hierarchy, which puts fast but expensive and small storage options close to the CPU and slower but larger and cheaper options farther away; the fast volatile technologies are referred to as "memory", while slower persistent technologies are referred to as "storage". In the Von Neumann architecture, the CPU consists of two main parts: The control unit and the arithmetic logic unit; the former controls the flow of data between the CPU and memory, while the latter performs arithmetic and logical operations on data. Without a significant amount of memory, a computer would be able to perform fixed operations and output the result, it would have to be reconfigured to change its behavior. This is acceptable for devices such as desk calculators, digital signal processors, other specialized devices.
Von Neumann machines differ in having a memory in which they store their operating instructions and data. Such computers are more versatile in that they do not need to have their hardware reconfigured for each new program, but can be reprogrammed with new in-memory instructions. Most modern computers are von Neumann machines. A modern digital computer represents data using the binary numeral system. Text, pictures and nearly any other form of information can be converted into a string of bits, or binary digits, each of which has a value of 1 or 0; the most common unit of storage is the byte, equal to 8 bits. A piece of information can be handled by any computer or device whose storage space is large enough to accommodate the binary representation of the piece of information, or data. For example, the complete works of Shakespeare, about 1250 pages in print, can be stored in about five megabytes with one byte per character. Data are encoded by assigning a bit pattern to digit, or multimedia object.
Many standards exist for encoding. By adding bits to each encoded unit, redundancy allows the computer to both detect errors in coded data and correct them based on mathematical algorithms. Errors occur in low probabilities due to random bit value flipping, or "physical bit fatigue", loss of the physical bit in storage of its ability to maintain a distinguishable value, or due to errors in inter or intra-computer communication. A random bit flip is corrected upon detection. A bit, or a group of malfunctioning physical bits is automatically fenced-out, taken out of use by the device, replaced with another functioning equivalent group in the device, where the corrected bit values are restored; the cyclic redundancy check method is used in communications and storage for error detection. A detected error is retried. Data compression methods allow in many cases to represent a string of bits by a shorter bit string and reconstruct the original string when needed; this utilizes less storage for many types of data at the cost of more computation.
Analysis of trade-off between storage cost saving and costs of related computations and possible delays in data availability is done before deciding whether to keep certain data compressed or not. For security reasons certain types of data may be kept encrypted in storage to prevent the possibility of unauthorized information reconstruction from chunks of storage snapshots; the lower a storage is in the hierarchy, the lesser its bandwidth and the greater its access latency is from the CPU. This traditional division of storage to primary, secondary and off-line storage is guided by cost per bit. In contemporary usage, "memory" is semiconductor storage read-write random-access memory DRAM or other forms of fast but temporary storage. "Storage" consists of storage devices and their media not directly accessible by the CPU hard disk drives, optical disc drives, other devices slower than RAM but non-volatile. Memory has been called core memory, main memory, real storage or internal memory. Meanwhile, non-volatile storage devices have been referred to as secondary storage, external memory or auxiliary/peripheral storage.
Primary storage referred to as memory, is the only one directly accessible to the CPU. The CPU continuously reads instructions executes them as required. Any data operated on is stored there in uniform manner. Early computers used delay lines, Williams tubes, or rotating magnetic drums as primary storage. By 1954, those unreliable methods were replaced by magnetic core memory. Core memory remained dominant until the 1970s, when advances in integrated circuit technology allowed semiconductor memory to become economically competitive; this led to modern random-access memo
The TI-89 and the TI-89 Titanium are graphing calculators developed by Texas Instruments. They are differentiated from most other TI graphing calculators by their computer algebra system, which allows symbolic manipulation of algebraic expressions—equations can be solved in terms of variables, whereas the TI-83/84 series can only give a numeric result; the TI-89 is a graphing calculator developed by Texas Instruments in 1998. The unit features a 160×100 pixel resolution LCD screen and a large amount of flash memory, includes TI's Advanced Mathematics Software; the TI-89 is one of the highest model lines in TI's calculator products, along with the TI-Nspire. In the summer of 2004, the standard TI-89 was replaced by the TI-89 Titanium; the TI-89 runs on a 16-bit microprocessor, the Motorola 68000, which nominally runs at 10, 12 MHz, depending on the calculator's hardware version. Texas Instruments has allocated 256 total kB of RAM for 2 MB of flash memory; the RAM and Flash ROM are used to store expressions, programs, text files, lists.
The TI-89 is a TI-92 Plus with a limited keyboard and smaller screen. It was created in response to the fact that while calculators are allowed on many standardized tests, the TI-92 was considered a computer due to the QWERTY layout of its keyboard. Additionally, some people found the TI-92 overly large; the TI-89 is smaller—about the same size as most other graphing calculators. It has a flash ROM, a feature present on the TI-92 Plus but not on the original TI-92; the major advantage of the TI-89 over lower-model TI calculators is its built-in computer algebra system, or CAS. The calculator can simplify algebraic expressions symbolically. For example, entering x^2-4x+4 returns x 2 − 4 x + 4; the answer is "prettyprinted" by default. The TI-89's abilities include: Algebraic factoring of expressions, including partial fraction decomposition. Algebraic simplification. Evaluation of trigonometric expressions to exact values. For example, sin returns 3 2 instead of 0.86603. Solving equations for a certain variable.
The CAS can solve for one variable in terms of others. For equations such as quadratics where there are multiple solutions, it returns all of them. Equations with infinitely many solutions are solved by introducing arbitrary constants: solve returns x=2. with the @n1 representing any integer. Finding limits of functions, including infinite limits and limits from one direction. Symbolic differentiation and integration. Derivatives and definite integrals are evaluated when possible, otherwise. In addition to the standard two-dimensional function plots, it can produce graphs of parametric equations, polar equations, sequence plots, differential equation fields, three-dimensional functions; the TI-89 is directly programmable in a language called TI-BASIC, TI's derivative of BASIC for calculators. With the use of a PC, it is possible to develop more complex programs in Motorola 68000 assembly language or C, translate them to machine language, copy them to the calculator. Two software development kits for C programming are available.
Since the TI-89's release in 1998, thousands of programs for math, science, or entertainment have been developed. Many available games are generic clones of Tetris and other classic games, but some programs are more advanced: for example, a ZX Spectrum emulator, a chess-playing program, a symbolic circuit simulator, a clone of Link's Awakening. One of the most popular and well-known games is Phoenix. Many calculator games and other useful programs can be found on TI-program sharing sites. Ticalc.org is a major one. There are four hardware versions of the TI-89; these versions are referred to as HW1, HW2, HW3, HW4. Entering the key sequence displays the hardware version. Older OS versions don't display anything about the hardware version unless the calculator is HW2 or later; the differences in the hardware versions are not well documented by Texas Instruments. HW1 and HW2 correspond to the original TI-89; the most significant difference between HW1 and HW2 is in the way the calculator handles the display.
In HW1 calculators there is a video buffer that stores all of the information that should be displayed on the screen, every time the screen is refreshed the calculator accesses this buffer and flushes it to the display. In HW2 and calculators, a region of memory is directly aliased to the display controller; this allows for faster memory access, as the HW1's DMA controller used about 10% of the bus bandwidth. However, it interferes with a trick some programs use to implement grayscale graphics by switching between two or more displays. On the HW1, the DMA controller's base address can be changed and th
The TI 73 series is a series of graphing calculators made by Texas Instruments, all of which have identical hardware. The original TI-73 graphing calculator was designed in 1998 as a replacement for the TI-80 for use at a middle school level, its primary advantage over the TI-80 is its 512 KB of flash memory, which holds the calculator's operating system and thereby allows the calculator to be upgraded. Other advantages over the TI-80 are the TI-73's standard sized screen, the addition of a link port, 25 KB of RAM, a faster 6 MHz Zilog Z80 processor; the TI-73 uses the standard 4 AAA batteries with a lithium backup battery. In 2003, the TI-73 was redesigned with a sleek new body shape and redesignated the TI-73 Explorer to indicate its intended use as a bridge between the TI-15 Explorer and similar calculators and the TI-83 Plus, TI-84 Plus, similar calculators; the TI-73 Explorer was remodeled to resemble the TI-84 Plus graphing calculator more closely. Due to lack of demand in middle schools, the TI-73 and TI-73 Explorer have not been huge sellers for TI and are not carried by most retail stores.
Most American upper-level middle school algebra courses tend to use the TI-83 or TI-84 families instead of the TI-73 or TI-73 Explorer, while most basic middle school math courses do not use graphing calculators, instead opting for scientific calculators such as the TI-30 or TI-34 families. The TI-73 could only run programs written in TI-BASIC, although that has changed in recent years. In 2005 an assembly shell called Mallard was released for the TI-73. Mallard allows the user to run programs written in assembly language; as with the TI-82 and the TI-85 before, a hacked backup file is downloaded containing the assembly shell. Released in late 2008, the Windows utility Chameleon allows a user to load the TI-73 Explorer with a modified TI-83+ firmware, giving it nearly equivalent functionality. In 2009, Texas Instruments updated the skin of the TI-73 Explorer to match the shape of the larger TI-84 Plus's case; this resulted in a slight increase in mass from 182 grams to 208 grams. The hardware and software remained unchanged and is identical to an older unit wearing the TI-83 plus style casing.
CPU: Zilog Z80 CPU, 6 MHz Flash ROM: 512 KB with 128 KB available for Flash Applications RAM: 32 KB with 25 KB available to the user Display: Text: 16×8 characters I/O Link port 50 button built-in interface Power: 4 AAA batteries plus 1 lithium battery for backup Integrated programming languages: TI-BASIC Comparison of Texas Instruments graphing calculators Features of the TI-73 Explorer Some TI-73 programs and the Chameleon utility can be found at ticalc.org and several others at CalcG.org