General

General Category

Generic technology terms explained

Volume

A logical division of data, comprising of a number of files. In the context of hard disk drives, a volume is formatted by using a file system – such as FAT or NTFS – and has a drive letter assigned to it. A single hard disk can have multiple volumes and, unlike partitions, volumes can span multiple disks. Under the ISO 9660 standard, a “volume” refers to a single CD-ROM disc.

VESA

Video Electronics Standards Association: an international non-profit organisation established in 1989 to set and support industry-wide interface standards designed for the PC, workstation, and other computing environments. The VESA Local Bus (VL-Bus) standard – introduced in 1992 and widely used before the advent of PCI – was a 32-bit local bus standard compatible with both ISA and EISA cards.

VAR

Value Added Reseller: a company which resells hardware and software packages to developers and/or end-users.

UNIX

A multi-user, multiprocessor operating system developed by AT&T in the early 1970s. It exists in various forms and implementations and is the predominant operating system used by the Internet servers. It is not, however, required by the user to access the Internet.

TiB

Tebibyte: a unit of measure consisting of 1024GiB.

Terabyte: a unit of measure for storage capacity 1,000,000,000,000 (1 trillion) bytes, or 1,000,000 (1 million) megabytes or 1,000 (1 thousand) gigabytes.

Synchronous

Refers to events that are synchronised, or co-ordinated, in time. Communication within a computer is usually synchronous and is governed by the microprocessor clock. Signals along the bus, for example, can occur only at specific points in the clock cycle.

Substrate

The underlying material on which a microelectronic device or storage media is built. Silicon is the most widely used substrate for chips, fibreglass for printed circuit boards and ceramic for multichip modules. Aluminium is commonly used for hard disks, glass for optical disks and mylar for floppy disks.

SQL

Structured Query Language: a query language developed by IBM that relies on simple English-language statements to perform database queries. Almost universally supported in one form or another by relational databases on platforms of all types, SQL allows databases from different manufacturers and on different types of computers to be queried using a standard syntax. See also ODBC.

SOHO

Small Office/Home Office: refers to the small business or business-at-home user. This market segment has benefited greatly from recent technological advances, allowing it to compete on a level playing ground with the bigger companies.

RTF

Rich Text Format: a format in common use by word processors. It accepts both text and images, and retains text formatting and page layout.

RPM

Revolutions Per Minute.

Removable Storage

A type of storage which allows the actual storage media to be removed from a drive and replace it with other media. It is used for the transportation of data between computers and for data backup.
Read More

Real-time

In computing, refers to an operating mode under which data is received and processed and the results returned so quickly as to seem instantaneous.

Random Access

Ability to access any particular block by going directly to it. Memory and disk devices support random access; by contrast, tape storage devices do not.

PSK

Phase Shift Keying: a data transmission technique that blends a data signal into a carrier by varying (modulating) the phase of the carrier by a certain number of degrees for each succeeding signal.
Read More

Protocol

A formal set of rules and descriptions of information formats that allow two computers to exchange information.

PS/2

An IBM personal computer series introduced in 1987, superseding the original PC line. It introduced the 3.5in floppy disk, VGA graphics and Micro Channel bus. The latter has since given way to the PCI bus.

Protected Mode

A memory-addressing system supporting 32-bit instruction sets. I t mediates between different programs running at once, and keeps them within their memory boundaries.

POSIX

Portable Operating System Interface for UNIX: a set of IEEE and ISO standards that define an interface between programs and operating systems. By designing their programs to conform to POSIX, developers have some assurance that their software can be easily ported to POSIX-compliant operating systems. This includes most varieties of UNIX.

PnP

Plug and Play: a Microsoft/Intel specification that allows for self-configuration of computers and peripherals. A fully Plug and Play-enabled PC requires three PnP components: a PnP BIOS, PnP adapters and peripherals, and a PnP operating system. Adding a PnP-compliant device to a PnP PC requires little more than making the physical connection. The operating system, in conjunction with PnP logic present in the BIOS and in the device itself, handles the IRQ settings, I/O addresses, and other technical aspects of the installation to ensure that the device does not conflict with other installed devices.

Picolitre

pl: a million millionth of a litre.

PIC

Programmable Interrupt Controller: a chip or device that prioritises interrupt requests generated by keyboards, serial ports, and other devices and passes them on to the CPU in order of highest priority. See also IRQ.

Peripheral

Any hardware device – such as a disk drive, tape drive, printer or modem – added to a system as a complement to the basic CPU.

PDA

Personal Digital Assistant: a handheld device that combines computing, telephone/fax, and networking features. A typical PDA can function as a cellular phone, fax sender, and personal organiser. Some PDAs are hand-held PC with tiny keyboards. Another class of device uses a touch-screen and stylus for data entry.
Read More

PCMCIA

Personal Computer Memory Card International Association: a consortium of computer manufacturers that devised the standard for the credit card-size adapter cards used in many notebook computers. PCMCIA defines three card types: Type I cards can be up to 3.3mm thick and are generally used for RAM and ROM expansion cards; Type II cards can be as thick as 5.5mm and typically house modems and fax modems; Type III cards are the largest of the lot (up to 10.5mm thick) and are mostly used for solid state disks or miniature hard disks. PCMCIA cards are also known as “PC Cards”.
Read More

PCB

Printed Circuit Board: a board upon which there are layers of printed circuits and onto which other integrated circuits can be soldered or otherwise attached.

Overrun

The condition occurring when data is transmitted to a receiving device at a rate that’s too fast for it to handle. See also Underrun and Flow Control.

OSR

OEM Service Release: a version of Windows 95 incorporating bug fixes and new functionality released to PC vendors for bundling with new PCs. Not available as an upgrade to older versions of Windows 95.

Oscilloscope

A test instrument that displays electronic signals (waves and pulses) on a screen. It creates its own time base against which signals can be measured, and display frames can be frozen for visual inspection.

Operating System: the software controlling the overall operation of a multipurpose computer system, including such tasks as memory allocation, input and output distribution, interrupt processing, and job scheduling.

OLE

Object Linking and Embedding: an industry-standard method for inserting an object into a document. The document retains a connection, or link, with its original program so that double-clicking on the object in the document opens the object’s original program. See also DLL.

OEM

Original Equipment Manufacturer: a company which develops, produces and sells computer and consumer hardware.

ODBC

Open Database Connectivity: a standard promulgated by Microsoft that allows databases created by various database management programs-such as DBASE, Microsoft Access, Microsoft FoxPro, and Oracle to be accessed using a common interface independent of the database file format. By relying on ODBC, one can write an application that uses the same code to read records from a DBASE file or a FoxPro file. Internally, ODBC drivers use a form of SQL to carry out database operations. See also SQL and WOSA.

NTFS

NT File System: the file system that is native to Microsoft Windows NT. NTFS is probably the most advanced file system available for personal computers, featuring superior performance, excellent security and crash protection, and the ability to handle large volumes of data.

Noise

Interference (static) that destroys the integrity of signals on electronic highways or communications lines. Noise can come from a variety of sources, including radio waves, nearby electrical wires, lightning, and bad connections. Noise is an analogue problem; once a signal is digitised, it is relatively immune to noise.

NMI

NonMaskable Interrupt: a high-priority interrupt that cannot be disabled by another interrupt. It is used to report malfunctions such as parity, bus and math co-processor errors.

Network

A group of two or more computer systems linked together. There are many types of computer networks, including LANs and WANs.

Nanosecond

ns: one thousand-millionths of a second of a second (.000000001 sec.). Light travels approximately 8 inches in 1 nanosecond.

Nanometre

nm: one thousand millionth of a metre.

Multithreading

Multiple concurrent threads of execution within a single application.

Multitasking

The concurrent execution of several jobs.

MTBF

Mean Time Between Failure: the average time a specific component is expected to work without failure.

MTTR

Mean Time To Repair: the average time to repair a specific component.

Moore’s Law

It was in 1965, three years before he was to become a co-founder of Intel Corporation, that Gordon Moore made the famous prediction that would thereafter be referred to as “Moore’s Law” – that the number of transistors per integrated circuit would double every 18 months. Moore forecast that the trend would continue through 1975; in fact it has been maintained for far longer.
Read More

MOPS

Millions of Operations Per Second.

MIPS

Millions of Instructions Per Second: refers to a computer processor’s performance and is the benchmark for comparing standard for CPUs.

Millisecond – ms

One thousandth of a second – 0.001 sec.

Microsecond

Âµs: one millionth of a second (.000001 sec.).

Micron

Âµm: a unit of measure equivalent to one-millionth of a metre; synonymous with micrometre.

Microcode

The lowest-level instructions that directly control a microprocessor. A single machine-language instruction typically translates into several microcode instructions. In modern PC microprocessors, the microcode is hard-wired and can’t be modified.

MHz

Megahertz: a measurement of frequency in millions of cycles per second.

MiB

Mebibyte: a unit of measure consisting of 1024KiB.

Mflops

Megaflops: 1 million floating-point instructions per second.

Media

A component used to store data such as a tape, floppy disk or CD-ROM.

MBps

Megabytes per second: a performance measure used for mass storage devices and memory systems.

Megabyte – MB

A megabyte (derived from the Standards Insitute prefix mega-, meaning a million) is a unit of information or computer storage that the Standards Insititute defines as one million (10^6) bytes. With memory, however, it is commonly given the quantity of 1,048,576 bytes (2^20). A megabyte is abbreviated MB.

Mask

Used like stencils in the chip making process. When used with the UV light, masks create the various circuit patterns on each layer of the microprocessor. Also used to describe the information in the alpha channel of a graphic that determines how effects are rendered.

Macintosh

Introduced by Apple Computer in 1984, the Macintosh marked a breakthrough in personal computer technology, featuring a graphical user interface (GUI) that utilised windows, icons and a mouse. The success of the Macintosh GUI led heralded a new age of graphics-based applications and operating systems, Microsoft’s subsequent Windows interface copying many features from the Mac.

Low Profile

Describes drives built to the 3.5in form factor, which are only 1in high. The standard form factor drives are 1.625in high.

Legacy

Term used to describe an application, architecture, protocol, system or system component etc. that has been in existence for a long time.

Latency

The time between initiating a request for data and the beginning of the actual data transfer. For example, the average latency of a hard disk drive is easily calculated from the spindle speed, as the time for half a rotation. In communications, network latency is the delay introduced when a packet is momentarily stored, analysed and then forwarded.

KiB

Kibibyte: a unit of measure consisting of 1024 bytes. One of the names and symbols for prefixes for binary multiples for use in the fields of data processing and data transmission approved as an IEC International Standard in December 1998. See also MiB, GiB and TiB.

KBps

Kilobytes per second: a performance measure used for mass storage devices and memory systems.

Kbit

Kilobit: a unit of measure consisting of 1000 bits. The unit often used in expressions of data transmission capacity.

Kilobyte (KB)

A kilobyte (derived from the Standards Insitute prefix kilo-, meaning 1000) is a unit of information or computer storage defined by the Standards Institute as 1000 bytes. Abbreviations for kilobyte include KB, kB, Kbyte, and kbyte. Note that “kilobyte” is also used to represent 1024 (2^10) bytes, though the preferred term for this is a kibibyte (KiB).

Isochronous

Refers to processes where data must be delivered within certain time constraints. For example, multimedia streams require an isochronous transport mechanism to ensure that data is delivered as fast as it is displayed and to ensure that the audio is synchronised with the video. Contrast with Asynchronous and Synchronous.

ISO

International Standards Organisation: an international body responsible for establishing and managing various standards committees and expert groups, including several image-compression standards.

Internet

The global computer network, composed of thousands of WANs and LANs that uses TCP/IP to provide world-wide communications to homes, schools, businesses and governments. The WWW runs on the Internet.

Interface

A hardware or software protocol, contained in the electronics of the disk controller and disk drive, that manages the exchange of data between the drive and computer. The most common interfaces for small computer systems are AT (IDE) and SCSI.

iMac

An Apple computer intended for home, school, and small offices, and promoted by Apple as an easy-to-use, stylish computer that outperforms other low-cost options. The computer comes equipped with a 233MHz G3 processor, 32 MB SDRAM, 4GB hard disk drive, a 56K modem, and a Universal Serial Bus (USB), which allows a user to add devices without restarting the computer. Controversially, the iMac does not come with a floppy disk drive. Easily recognisable for its translucent blue casing, the computer sold quickly after its introduction in the summer of 1998.

IEEE

Institute of Electrical and Electronics Engineers: a membership organisation that includes engineers, scientists and students in electronics and allied fields. Best known for its involvement in setting standards for computers and communications, such as the widely followed IEEE 802 standards for Local Area Networks.

IEC

International Electrotechnical Commission: the body that attempted to resolve the confusion surrounding the use of “MB” to mean either binary megabytes and decimal megabytes – depending on context – by their approval, in late 1998, of names and symbols for prefixes for binary multiples for use in the fields of data processing and data transmission. The acceptance of the symbols – “Ki”, “Mi”, “Gi” etc. – by the PC industry has been somewhat disappointing.

IBM PC

IBM created the PC industry when it launched its first PC in 1981. They were named PC, XT, AT etc.

I/O Address

Memory location for a particular device (disk drive, sound card, printer port, etc.). Two devices cannot share the same I/O address space.

I/O

Input/Output: refers to data transfer from input devices (keyboard, mouse, scanner, etc.) to output devices (printer, screen, etc.).

Hertz: the number of times something happens a second.

Huffman Coding

For a given character distribution, by assigning short codes to frequently occurring characters and longer codes to infrequently occurring characters, Huffman’s minimum redundancy encoding minimises the average number of bytes required to represent the characters in a text.

HSM

Hierarchical Storage Management: System of ranking and storing information across a variety of device types.

GPF

General Protection Fault: the error code triggered when a Windows program causes a failure or lock-up.

GOPS

Giga Operations Per Second: in the case of multimedia processing, more GOPS translate to better video quality.

GiB

Gibibyte: a unit of measure consisting of 1024MiB.

Gflops

Gigaflops: 1 thousand million floating-point instructions per second.

GBps

Gigabytes per second: a performance measure used for mass storage devices and memory systems.

Gigabyte: a unit of measure consisting of 1000MB.

Format

A preparatory process that is necessary before data can be recorded to some storage devices. Formatting erases any previously stored data.

Form Factor

The physical size and shape of a device. It is often used to describe the size of circuit boards. The physical size of a device as measured by outside dimensions. With regard to a disk drive, the form factor is the overall diameter of the platters and case, such as 3.5in or 5.25in, not the size in terms of storage capacity. If the drive is a 5.25in form factor it means that the drive is the same size as a 5.25in diskette drive and uses the same fixing points.
Read More

Firmware

Permanent instructions and data programmed directly into the circuitry of read-only memory for controlling the operation of the computer or peripheral devices. Distinct from software, which is stored in read/write memory and can be altered.

File Server

A computer that provides network stations with controlled access to shareable resources. The network operating system is loaded on the file server, and most shareable devices (disk subsystems, printers) are attached to it. The file server controls system security and monitors station-to-station communications. A dedicated file server can be used only as a file server while it is on the network. A non-dedicated file server can be used simultaneously as a file server and a workstation.

Expansion Card

A circuit board that fits into a computer expansion slot to add a certain function (like a modem, sound card, or SCSI interface).

Encoding

A method whereby a group of data bits is translated into a group of recording bits.

EIA

Electronic Industries Association: a trade association representing the U.S. high technology community which began life in 1924 as the Radio Manufacturers Association. It has been responsible for developing some important standards, such as the RS-232, RS-422 and RS-423 standards for connecting serial devices. In 1988, it spun off its Information & Telecommunications Technology Group into a separate organisation known as the TIA.

EDVAC

Electronic Discrete Variable Automatic Computer: the first computer to incorporate von Neumann’s “stored program” concept, in which the programme executed by the computer was stored as data, rather than existing as wire connections. Designed in 1946, when EDVAC became fully operational in 1952 it comprised contained approximately 4,000 vacuum tubes and 10,000 crystal diodes.

Dual Boot

Allows the computer to boot to two different operating systems (DOS and UNIX, for example).

DTR

Data Transfer Rate: the speed at which data is transferred between a host and a data recording device. Usually noted in KBps or MBps, and sometimes in MB/minute. Can mean a “peak” rather than a “sustained” transfer rate.

Drive Bay

Refers to a site in a where many mass storage devices can be internally installed. Usually a 5.25in-wide 1in-tall hole in a computer case. The number of drive bays in a computer determines how many such devices can be internally installed. The other common size is 3.5in. Bays are described as either internal or exposed. An internal bay is meant for hard disk drives, an exposed bay for removable media drives, such as a CD-ROM, tape backup or floppy disk unit. Some manufacturers use the terms hidden and accessible in place of internal and exposed.

DLL

Dynamic Link Library: a special type of Windows program containing functions that other programs can call, resources (such as icons) that other programs can use, or both. Unlike a standard programming library, whose functions are linked into an application when the application’s code is compiled, an application that uses functions in a DLL links with those functions at runtime – hence the term “dynamic”.

Directory

An area or data structure in which information is stored regarding the location and contents of files and/or file structures. Also called directory partition.

DIN Connector

A German standard used mostly for audio applications. DIN connectors are used for keyboards, PS/2 style mice, MIDI, and Apple printer attachments.

Device Driver

A software routine that links a peripheral device to the operating system. It acts like a translator between a device and the applications that use it. Each device has its own set of specialised commands known only to its driver. In contrast, most applications access devices by using high-level, generic commands. The driver accepts these generic and translates them into the low-level specialised commands required by the device.

DDE

Dynamic Date Exchange: a mechanism used in Windows to transfer data between two applications or two separate instances of the same application. Windows itself uses DDE for a variety of purposes, from opening documents in running applications when a document icon is double-clicked in the shell to obtaining program icons for DOS applications. DDE is also used to support OLE. See also OLE.

Daughter Board

A printed circuit board that plugs into another circuit board (usually the motherboard). It is similar to an expansion board, but accesses the motherboard components (memory and CPU) directly rather than through the slower expansion bus.

Direct Current: an electrical current that travels in one direction and used within the computer’s electronic circuits. Contrast with AC.

DAC

Digital-to-Analogue Converter: a device (usually a single chip) that converts digital data into analogue signals. Graphics cards have traditionally required DACs to convert digital data to analogue signals that a monitor can process. Modems require a DAC to convert data to analogue signals that can be carried by telephone wires.

Crosstalk

Interference from an adjacent electronics circuitry.

CRC

Cyclical Redundancy Check: a complex mathematical method that permits errors in long runs of data to be detected with a very high degree of accuracy.

COMDEX

COMputer Dealers EXposition: a twice yearly – once in the spring (in Atlanta) and once in autumn (in Las Vegas) – trade show originally created for computer dealers and distributors but nowadays also attended by large numbers of end users. The first COMDEX in the autumn of 1979 had 157 exhibitors and 4,000 attendees. By the end of the millennium the events were attracting more than 2,000 exhibitors and 200,000 people annually.

COM Port

The connectors and accompanying circuitry that allow serial devices – such as serial printers, modems, or mice – to be connected to PC. Communication ports are also called serial ports. To keep track of the devices, DOS assigns names that begin with the letters COM to communication ports (such as COM1 and COM2).

Clone

Any computer system compatible with the IBM PC standard.

CeBIT

A computer exhibition hosted in Hannover, Germany in the spring of each year. The exhibition is a spin-off from the more broadly-based Hannover Fair trade show and debuted in 1986.

CCIR

Consultative Committee for International Radio communications.

CCIA

Computer and Communications Industry Association: a trade association composed of computer and communications firms. It represents their interests in domestic and foreign trade, and keeps members advised of relevant standards and regulatory policy.

Capacity

Generally quantifies the amount of data that can be stored on a storage device. Capacity is usually expressed in megabytes, meaning millions of bytes. This contrasts with RAM, where a megabyte refers to 1,048,576 bytes.

Byte

Eight bits treated as a unit and representing a character.

Bus

An electronic traffic lane through which electrical signals are carried from one chip to another chip. Most often used in the context of communication between the processor and other system components. There are many different kinds of bus including ISA, EISA, MCA and the local bus standards PCI and VL-Bus.

Buffer

A storage location used for temporary storage of data read from or waiting to be sent to some device. Use of a memory buffer – often referred to as a “cache” – is used to speed up access to many devices, such as a hard disk, CD-ROM or tape drive.

Breakout

In simple terms a breakout is something that takes a grouped set and breaks it into its constituent parts. For example, a breakout box might be used to separate out the individual inputs and/or outputs of a single optical cable carrying multiple channels of audio.

BPI

Bits Per Inch: a measure of how densely information is packed on a storage medium. See also Flux Density.

Boot Drive

The drive that the operating system first loads from (usually :A: or :C).

Block

Data is organised into logical “blocks” for transmission between devices. Blocks may be fixed or variable length, with block sizes of 512 or 1024 bytes being particulary common. An example of a block format is: preamble, user data, CRC, postamble.

Bit

A Binary Digit is the basic binary unit for storing data. It can either be 0 or 1. It takes 8 bits to equal a byte.

Binary

Pertaining to a number system that has just two unique digits. For most purposes, the decimal number system is used, which has ten unique digits, 0 through 9. All other numbers are then formed by combining these ten digits. Computers are based on the binary numbering system, which consists of just two unique numbers, 0 and 1. All operations that are possible in the decimal system (addition, subtraction, multiplication, division) are equally possible in the binary system.

BBS

Bulletin Board System: a term for dial-up on-line systems from which to download software, leave messages for other users, and exchange information. BBBs proliferated in the 1980s before the WWW became popular. A BBS functions somewhat like a stand-alone Web site, but without graphics. However, unlike Web sites, each BBS has its own telephone number to dial into.

Bandwidth

The amount of data that can be moved through a particular interface in a given period of time, e.g. a 64-bit wide, 100 MHz SDRAM data bus has a bandwidth of 800 MBps.

Backup

A copy of a file, directory, or volume on a separate storage device from the original, for the purpose of retrieval in case the original is accidentally erased, damaged, or destroyed.

Asynchronous

Refers to events that are not synchronised, or co-ordinated, in time. Most communication between computers and devices is asynchronous – it can occur at any time and at irregular intervals.

ASPI

Advanced SCSI Protocol Interface: an interface standard developed by Adaptec Inc. that has become one of the major SCSI interface standards for computers.

ASIC

Application Specific Integrated Circuit: an integrated circuit chip designed for a particular use rather than general use. Many video boards and modems use ASICs.

ASCII

American Standard Code for Information Interchange: a standard developed by the American National Standards Institute (ANSI) describing how characters can be represented on a computer. The ASCII character set consists of 128 characters numbered from 0 to 127 and includes numerals, punctuation symbols, letters, and special control codes such as end-of-line characters. Most personal computers use some form of the ASCII character set.

Archive

Long-term on- and/or off-site storage.

API

Application Programming Interface: a set of subroutines or functions that a program, or application, can call to tell the operating system to perform some task. The Windows API consists of more than 1,000 functions that programs written in C, C++, Pascal, and other languages can call to create windows, open files, and perform other essential tasks.

ANSI

American National Standards Institute. A standards-setting, non-government organisation which develops and publishes standards for voluntary use in the United States.

Artificial Intelligence: the branch of computer science concerned with making computers behave like humans. Applications include: games playing, expert systems, natural language and robotics. AI also implies the ability to learn or adapt through experience.

Analogue-to-Digital Converter – ADC

A device that converts continuously varying analogue signals from instruments that monitor such conditions as movement, temperature, sound, etc., into binary code for the computer. It may be contained on a single chip or can be one circuit within a chip.

Access

Read, write, or update information on some storage medium, such as a disk.

Aternating Current: the common form of electricity from power plant to home/office. Its direction is reversed 60 times per second in the U.S.; 50 times in Europe. Contrast with DC.

WOSA

Windows Open Services Architecture: a collection of APIs that provide standard ways for Windows applications to access databases, telephony devices, messaging services, and other services. ODBC and MAPI are two examples of APIs that fall under the WOSA umbrella.

WYSIWYG

What You See Is What You Get: screen output that exactly (or very closely) matches the appearance of printed output. WYSIWYG displays were once rare on the PC platform, because most applications ran in character mode and had little control over the format of text rendered on the screen. Today WYSIWYG applications abound, because Windows allows more precise control over screen formatting and provides a device-independent interface to both screens and printers.

MEMS

Micro-electromechanical systems: the name for technology that embeds mechanical devices such as fluid sensors, mirrors, actuators, pressure and temperature sensors, vibration sensors and valves in semiconductor chips. MEMS combine many disciplines, including physics, bioinformatics, biochemistry, electrical engineering, optics and electronics.

ECMA

European Computer Manufacturers Association; a non-profit international industry association founded in 1961 dedicated to the worldwide standardisation of information and communication systems, and responsible spearheading the development of a standard for holographic information storage.

Other definitions:

General Category

Generic technology terms explained

Recent Posts

5 Tips to Secure Your Computer While Working From Home

Oursurfing.com Virus Removal Guide

Typo 2 Keyboard Case for iPhone 6