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76-943: The minimum speed at which a Blu-ray Disc can be written is 36 megabits (4.5 megabytes) per second. As of 2024, one of the primary pioneers of the Blu-ray disc, Sony, is winding down production of recordable Blu-ray discs in its plant in Tagajo, Japan. Sony plans to gradually cease its manufacturing of optical media, including recordable Blu-ray discs. As of November 2022, there are five versions of BD-RE and four versions of BD-R formats. Each version includes three Parts (a.k.a. Books ): Basic Format Specifications, File System Specifications, Audio Visual Basic Specifications. Each part has sub-versions (e.g. R2 Format Specification includes Part 3: Audio Visual Basic Specifications Ver.3.02 , Part 2: File System Specifications Ver. 1.11 , Part 1: Basic Format Specifications Ver. 1.3 ). Inspite of having

152-427: A phase transition alloy (often GeSbTe or InAgTeSb ; copper silicate (CuSi) or other alloys can also be used, like Verbatim's proprietary MABL) is used for BD-RE discs. Melting the material with a very high power beam turns it into an amorphous state with low reflectivity, while heating at a lower power erases it back to a crystalline state with high reflectivity. In BD-RE discs, the data layers are surrounded by

228-400: A 60-bit word without having to split a byte between one word and the next. If longer bytes were needed, 60 bits would, of course, no longer be ideal. With present applications, 1, 4, and 6 bits are the really important cases.     With 64-bit words, it would often be necessary to make some compromises, such as leaving 4 bits unused in a word when dealing with 6-bit bytes at

304-467: A 64-bit word length for Stretch. It also supports NSA 's requirement for 8-bit bytes. Werner's term "Byte" first popularized in this memo.     NB. This timeline erroneously specifies the birth date of the term "byte" as July 1956 , while Buchholz actually used the term as early as June 1956 .     [...] 60 is a multiple of 1, 2, 3, 4, 5, and 6. Hence bytes of length from 1 to 6 bits can be packed efficiently into

380-465: A birth certificate. But I am sure that "byte" is coming of age in 1977 with its 21st birthday.     Many have assumed that byte, meaning 8 bits, originated with the IBM System/360, which spread such bytes far and wide in the mid-1960s. The editor is correct in pointing out that the term goes back to the earlier Stretch computer (but incorrect in that Stretch was the first, not

456-472: A computer and for this reason it is the smallest addressable unit of memory in many computer architectures . To disambiguate arbitrarily sized bytes from the common 8-bit definition, network protocol documents such as the Internet Protocol ( RFC   791 ) refer to an 8-bit byte as an octet . Those bits in an octet are usually counted with numbering from 0 to 7 or 7 to 0 depending on

532-476: A convenience, because 1024 is approximately 1000 . This definition was popular in early decades of personal computing , with products like the Tandon 5 1 ⁄ 4 -inch DD floppy format (holding 368 640 bytes) being advertised as "360 KB", following the 1024 -byte convention. It was not universal, however. The Shugart SA-400 5 1 ⁄ 4 -inch floppy disk held 109,375 bytes unformatted, and

608-618: A feature called "Stream Recording" which enables full nominal write speed. Whether defect management is beneficial with mediocre media depends much on the individual medium and the drive's firmware. It works well with narrowly located bad spots but tends to fail more often than stream recording if the drive perceives reduced read quality on the whole medium. It may be desirable to deactivate write verification on undamaged media to save time when mass-producing physical copies of data, since errors are unlikely to occur on physically undamaged media. As of April 2018 (approximate pricing): Instead of

684-622: A firmware upgrade can enable devices to access BD-R LTH. Panasonic released such a firmware update in November 2007 for its DMR-BW200, DMR-BR100 and MR-BW900/BW800/BW700 models. Pioneer was expected to ship the first LTH BD drives in Spring 2008. Sony upgraded the PlayStation 3 firmware enabling BD-R LTH reading in March, 2008. In 2011, France's Ministry of Culture and Communication conducted

760-484: A full transmission unit usually additionally includes a start bit, 1 or 2 stop bits, and possibly a parity bit , and thus its size may vary from seven to twelve bits for five to eight bits of actual data. For synchronous communication the error checking usually uses bytes at the end of a frame .     Terms used here to describe the structure imposed by the machine design, in addition to bit , are listed below.      Byte denotes

836-475: A group of bits used to encode a character, or the number of bits transmitted in parallel to and from input-output units. A term other than character is used here because a given character may be represented in different applications by more than one code, and different codes may use different numbers of bits (i.e., different byte sizes). In input-output transmission the grouping of bits may be completely arbitrary and have no relation to actual characters. (The term

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912-406: A number of bits, treated as a unit, and usually representing a character or a part of a character.     NOTES:     1 The number of bits in a byte is fixed for a given data processing system.     2 The number of bits in a byte is usually 8.      We received the following from W Buchholz, one of the individuals who

988-511: A pair of dielectric Zinc Sulfur-Silicon Dioxide layers. An adhesive spacer layer and a semi-reflective layer are used for multi-layer discs. The recording and dielectric layers are all deposited using Sputtering . On multi-layer BD-RE discs, each GeSbTe recording layer is progressively thinner. So the first layer (L0) is 10 nm thick, L1 is 7.5 nm thick, L2 is 6 nm thick, and so on. The silver alloy reflective layers that are behind each recording layer also become progressively thinner, so

1064-407: A study on the suitability of data archival of LTH (low to high) discs compared to HTL (high to low) discs. The data they collected indicated that the overall quality of LTH discs is worse than HTL discs. MiB The byte is a unit of digital information that most commonly consists of eight bits . Historically, the byte was the number of bits used to encode a single character of text in

1140-548: A unit of logarithmic power ratio named after Alexander Graham Bell , creating a conflict with the IEC specification. However, little danger of confusion exists, because the bel is a rarely used unit. It is used primarily in its decadic fraction, the decibel (dB), for signal strength and sound pressure level measurements, while a unit for one-tenth of a byte, the decibyte, and other fractions, are only used in derived units, such as transmission rates. The lowercase letter o for octet

1216-405: A unit which "contains an unspecified amount of information ... capable of holding at least 64 distinct values ... at most 100 distinct values. On a binary computer a byte must therefore be composed of six bits". He notes that "Since 1975 or so, the word byte has come to mean a sequence of precisely eight binary digits...When we speak of bytes in connection with MIX we shall confine ourselves to

1292-668: Is 1024 bytes = 1024 bytes, one mebibyte (1 MiB) is 1024 bytes = 1 048 576 bytes, and so on. In 1999, Donald Knuth suggested calling the kibibyte a "large kilobyte" ( KKB ). The IEC adopted the IUPAC proposal and published the standard in January 1999. The IEC prefixes are part of the International System of Quantities . The IEC further specified that the kilobyte should only be used to refer to 1000 bytes. Lawsuits arising from alleged consumer confusion over

1368-510: Is coined from bite , but respelled to avoid accidental mutation to bit .)     A word consists of the number of data bits transmitted in parallel from or to memory in one memory cycle. Word size is thus defined as a structural property of the memory. (The term catena was coined for this purpose by the designers of the Bull GAMMA 60  [ fr ] computer.)      Block refers to

1444-460: Is defined as eight bits. It is a signed data type, holding values from −128 to 127. .NET programming languages, such as C# , define byte as an unsigned type, and the sbyte as a signed data type, holding values from 0 to 255, and −128 to 127 , respectively. In data transmission systems, the byte is used as a contiguous sequence of bits in a serial data stream, representing the smallest distinguished unit of data. For asynchronous communication

1520-455: Is defined as the symbol for octet in IEC ;80000-13 and is commonly used in languages such as French and Romanian , and is also combined with metric prefixes for multiples, for example ko and Mo. More than one system exists to define unit multiples based on the byte. Some systems are based on powers of 10 , following the International System of Units (SI), which defines for example

1596-672: Is defined to equal 1,000 bytes—is recommended by the International Electrotechnical Commission (IEC). The IEC standard defines eight such multiples, up to 1 yottabyte (YB), equal to 1000 bytes. The additional prefixes ronna- for 1000 and quetta- for 1000 were adopted by the International Bureau of Weights and Measures (BIPM) in 2022. This definition is most commonly used for data-rate units in computer networks , internal bus, hard drive and flash media transfer speeds, and for

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1672-618: Is equal to 1,024 (i.e., 2 ) bytes is defined by international standard IEC 80000-13 and is supported by national and international standards bodies ( BIPM , IEC , NIST ). The IEC standard defines eight such multiples, up to 1 yobibyte (YiB), equal to 1024 bytes. The natural binary counterparts to ronna- and quetta- were given in a consultation paper of the International Committee for Weights and Measures' Consultative Committee for Units (CCU) as robi- (Ri, 1024 ) and quebi- (Qi, 1024 ), but have not yet been adopted by

1748-428: Is exactly twice the capacity, unlike dual-layer DVDs, which only have less than twice the capacity as single-layer DVDs. BDXL discs store more per data layer, roughly 30 GiB, so they are able to store 100 GB in only three instead of four layers. No single-layer variant for BDXL exists, given that a first-generation BD-R DL disc already exceeds the capacity of one layer of a BDXL. There are variants with 100 GB and 128 GB,

1824-433: Is just as easy to use all six bits in alphanumeric work, or to handle bytes of only one bit for logical analysis, or to offset the bytes by any number of bits. All this can be done by pulling the appropriate shift diagonals. An analogous matrix arrangement is used to change from serial to parallel operation at the output of the adder. [...]     byte:     A string that consists of

1900-466: Is often called a nibble , also nybble , which is conveniently represented by a single hexadecimal digit. The term octet unambiguously specifies a size of eight bits. It is used extensively in protocol definitions. Historically, the term octad or octade was used to denote eight bits as well at least in Western Europe; however, this usage is no longer common. The exact origin of

1976-408: Is the first write-once media with such functionality. If not deactivated, the correctness of the written data is verified immediately after being written. Poorly readable data can be written again to an area of spare blocks, but the writing speed is halved during the entire writing process because only half of the disc rotations are for writing. Defect management can be deactivated by burn programs using

2052-545: Is the opposite of normal Blu-rays, whose reflectivity changes from high to low during writing. The advantage of BD-R LTH is it can protect a manufacturer's investment in DVD-R / CD-R manufacturing equipment because it does not require investing in new production lines and manufacturing equipment. Instead, the manufacturer only needs to modify current equipment. This is expected to lower the cost of disc manufacturing. Old Blu-ray players and recorders cannot utilize BD-R LTH; however,

2128-457: Is used here because a given character may be represented in different applications by more than one code, and different codes may use different numbers of bits (ie, different byte sizes). In input-output transmission the grouping of bits may be completely arbitrary and have no relation to actual characters. (The term is coined from bite , but respelled to avoid accidental mutation to bit. )      System/360 took over many of

2204-597: The IRE Transactions on Electronic Computers , June 1959, page 121. The notions of that paper were elaborated in Chapter 4 of Planning a Computer System (Project Stretch) , edited by W Buchholz, McGraw-Hill Book Company (1962). The rationale for coining the term was explained there on page 40 as follows: Byte denotes a group of bits used to encode a character, or the number of bits transmitted in parallel to and from input-output units. A term other than character

2280-554: The Absolute Time in Pregroove (ATIP), into the groove. DVD-R and DVD-RW have a constant wobble frequency of 140.6 kHz relying on data 'pits' beside the groove to convey information (Land pre-pit). DVD+R and DVD+RW have a constant wobble frequency of 817.4 kHz, but encodes its addressing information by periodically inverting the phase of the wobble signal (bi-phase modulation) to encode an exact address of

2356-649: The American Standard Code for Information Interchange (ASCII) as the Federal Information Processing Standard , which replaced the incompatible teleprinter codes in use by different branches of the U.S. government and universities during the 1960s. ASCII included the distinction of upper- and lowercase alphabets and a set of control characters to facilitate the transmission of written language as well as printing device functions, such as page advance and line feed, and

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2432-626: The International Union of Pure and Applied Chemistry 's (IUPAC) Interdivisional Committee on Nomenclature and Symbols attempted to resolve this ambiguity by proposing a set of binary prefixes for the powers of 1024, including kibi (kilobinary), mebi (megabinary), and gibi (gigabinary). In December 1998, the IEC addressed such multiple usages and definitions by adopting the IUPAC's proposed prefixes (kibi, mebi, gibi, etc.) to unambiguously denote powers of 1024. Thus one kibibyte (1 KiB)

2508-526: The bit endianness . The size of the byte has historically been hardware -dependent and no definitive standards existed that mandated the size. Sizes from 1 to 48 bits have been used. The six-bit character code was an often-used implementation in early encoding systems, and computers using six-bit and nine-bit bytes were common in the 1960s. These systems often had memory words of 12, 18, 24, 30, 36, 48, or 60 bits, corresponding to 2, 3, 4, 5, 6, 8, or 10 six-bit bytes, and persisted, in legacy systems, into

2584-471: The wobble frequency . The wobble frequency is commonly used as a synchronization source to achieve constant linear velocity while writing a disc, but has other uses as well depending on the type of disc. The frequencies quoted all assume that the disc is being written at the '1x' speed. The frequencies are appropriately higher for faster writing speeds. CD-R and CD-RW discs use a frequency modulated wobble of 140.6 kHz to encode information, such as

2660-478: The "Blu-ray" brand, "BDXL" is separate from the original "BD" format, meaning existing Blu-ray drives that predate the release of BDXL (mid-2010) do not support BDXL. Even Blu-ray drives released after then do not necessarily support BDXL unless explicitly stated. A single-layer Blu-ray disc (BD-R and BD-RE) has a capacity of 25,025,314,816 bytes, which are 23,866 MiB . A dual-layer Blu-ray disc (BD-R DL and BD-RE DL) has 50,050,629,632 bytes, which are 47,732 MiB. This

2736-519: The "Volume Space" in the UDF specification, and stores the file system, names of files and folders, and the file contents. The same area is referred to as the "program area" on the CD. Other information such as where the disc sessions and tracks are located and their length are stored outside this area. If the spare area is enabled, 256 MiB (268.435.456 bytes) are taken away from the "Volume Space" and reserved for

2812-512: The Adder. The Adder may accept all or only some of the bits.     Assume that it is desired to operate on 4 bit decimal digits , starting at the right. The 0-diagonal is pulsed first, sending out the six bits 0 to 5, of which the Adder accepts only the first four (0-3). Bits 4 and 5 are ignored. Next, the 4 diagonal is pulsed. This sends out bits 4 to 9, of which the last two are again ignored, and so on.     It

2888-515: The IEC and ISO. An alternative system of nomenclature for the same units (referred to here as the customary convention ), in which 1 kilobyte (KB) is equal to 1,024 bytes, 1 megabyte (MB) is equal to 1024 bytes and 1 gigabyte (GB) is equal to 1024 bytes is mentioned by a 1990s JEDEC standard. Only the first three multiples (up to GB) are mentioned by the JEDEC standard, which makes no mention of TB and larger. While confusing and incorrect,

2964-568: The L0 silver layer is 10 nm thick, the L1 layer is 9 nm thick, the L2 layer is 7 nm thick, and so on. The separation layers that separate the recording layers from one another also progressively become thinner. BD-R LTH is a write-once Blu-ray Disc format that features an organic dye recording layer . "Low To High" refers to the reflectivity changing from low to high during the burning process, which

3040-512: The Shift Matrix to be used to convert a 60-bit word , coming from Memory in parallel, into characters , or 'bytes' as we have called them, to be sent to the Adder serially. The 60 bits are dumped into magnetic cores on six different levels. Thus, if a 1 comes out of position 9, it appears in all six cores underneath. Pulsing any diagonal line will send the six bits stored along that line to

3116-478: The Stretch concepts, including the basic byte and word sizes, which are powers of 2. For economy, however, the byte size was fixed at the 8 bit maximum, and addressing at the bit level was replaced by byte addressing.     Since then the term byte has generally meant 8 bits, and it has thus passed into the general vocabulary.     Are there any other terms coined especially for

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3192-631: The System/360 led to the ubiquitous adoption of the eight-bit storage size, while in detail the EBCDIC and ASCII encoding schemes are different. In the early 1960s, AT&T introduced digital telephony on long-distance trunk lines . These used the eight-bit μ-law encoding . This large investment promised to reduce transmission costs for eight-bit data. In Volume 1 of The Art of Computer Programming (first published in 1968), Donald Knuth uses byte in his hypothetical MIX computer to denote

3268-591: The binary and decimal definitions of multiples of the byte have generally ended in favor of the manufacturers, with courts holding that the legal definition of gigabyte or GB is 1 GB = 1 000 000 000 (10 ) bytes (the decimal definition), rather than the binary definition (2 , i.e., 1 073 741 824 ). Specifically, the United States District Court for the Northern District of California held that "the U.S. Congress has deemed

3344-452: The capacities of most storage media , particularly hard drives , flash -based storage, and DVDs . Operating systems that use this definition include macOS , iOS , Ubuntu , and Debian . It is also consistent with the other uses of the SI prefixes in computing, such as CPU clock speeds or measures of performance . A system of units based on powers of 2 in which 1 kibibyte (KiB)

3420-445: The case of BD-RE, a phase-changing alloy) that decreases its reflectivity on recording, i.e. "High To Low". Sony , for example, uses an inorganic composite that splits into two laminar components with low reflectivity. Composites used may include BiN , Ge 3 N 4 , and Pd -doped tellurium suboxide . A pair of layers with copper alloy and silicon that combines on recording may alternatively be used. Similar to CD-RW and DVD-RW ,

3496-453: The computer field which have found their way into general dictionaries of English language?     1956 Summer: Gerrit Blaauw , Fred Brooks , Werner Buchholz , John Cocke and Jim Pomerene join the Stretch team. Lloyd Hunter provides transistor leadership.     1956 July [ sic ]: In a report Werner Buchholz lists the advantages of

3572-470: The computer, also referred to as the "host" system. As of December 2018, the following speeds are seen in Blu-Ray specifications for R/RE discs: 2× speeds are mandatory for all formats, with 4× and 6× being optional for non-XL BD-R media. Since BD-RE 5.0/BD-R 4.0, a read speed of 4× is mandatory for UHD support. Note: If write verification is enabled, as it may be by default on some burning software,

3648-635: The customary convention is used by the Microsoft Windows operating system and random-access memory capacity, such as main memory and CPU cache size, and in marketing and billing by telecommunication companies, such as Vodafone , AT&T , Orange and Telstra . For storage capacity, the customary convention was used by macOS and iOS through Mac OS X 10.6 Snow Leopard and iOS 10, after which they switched to units based on powers of 10. Various computer vendors have coined terms for data of various sizes, sometimes with different sizes for

3724-454: The decimal definition of gigabyte to be the 'preferred' one for the purposes of 'U.S. trade and commerce' [...] The California Legislature has likewise adopted the decimal system for all 'transactions in this state. ' " Earlier lawsuits had ended in settlement with no court ruling on the question, such as a lawsuit against drive manufacturer Western Digital . Western Digital settled the challenge and added explicit disclaimers to products that

3800-502: The file system overhead is larger. The spare area is where the drive stores addresses for unreadable sectors so they are replaced with new data in case. This is known as defect management and is handled internally by the drive, not by the computer's operating system. On some earlier formats, including the CD-RW and DVD±RW , defect management has to be handled by the UDF file system, meaning by

3876-473: The former sense of the word, harking back to the days when bytes were not yet standardized." The development of eight-bit microprocessors in the 1970s popularized this storage size. Microprocessors such as the Intel 8080 , the direct predecessor of the 8086 , could also perform a small number of operations on the four-bit pairs in a byte, such as the decimal-add-adjust (DAA) instruction. A four-bit quantity

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3952-566: The input and output. However, the LINK Computer can be equipped to edit out these gaps and to permit handling of bytes which are split between words. [...]     [...] The maximum input-output byte size for serial operation will now be 8 bits, not counting any error detection and correction bits. Thus, the Exchange will operate on an 8-bit byte basis, and any input-output units with less than 8 bits per byte will leave

4028-428: The instruction. It is a deliberate respelling of bite to avoid accidental mutation to bit . Another origin of byte for bit groups smaller than a computer's word size, and in particular groups of four bits , is on record by Louis G. Dooley, who claimed he coined the term while working with Jules Schwartz and Dick Beeler on an air defense system called SAGE at MIT Lincoln Laboratory in 1956 or 1957, which

4104-418: The integral data type unsigned char must hold at least 256 different values, and is represented by at least eight bits (clause 5.2.4.2.1). Various implementations of C and C++ reserve 8, 9, 16, 32, or 36 bits for the storage of a byte. In addition, the C and C++ standards require that there are no gaps between two bytes. This means every bit in memory is part of a byte. Java's primitive data type byte

4180-465: The last, of IBM's second-generation transistorized computers to be developed).     The first reference found in the files was contained in an internal memo written in June 1956 during the early days of developing Stretch . A byte was described as consisting of any number of parallel bits from one to six. Thus a byte was assumed to have a length appropriate for the occasion. Its first use

4256-411: The latter of which has slightly less capacity per data layer but one additional data layer. A 100 GB BDXL has three data layers and 100,103,356,416 bytes (95,466 MiB) of capacity, which is 2 MiB less than twice the capacity of a BD-R(E) DL, and a 128 GB BDXL has four data layers and 128,001,769,472 bytes (122,072 MiB) of capacity and only exists as write-once variant (BD-R XL). This area is referred to as

4332-629: The location on the spiral track (Address in Pregroove). The practical upshot of this arrangement is that the recording drive can navigate to an exact location on the DVD+R(W) disc whereas it cannot do so with the DVD-R(W). BD-R and BD-RE discs utilise Address in Pregroove. HD DVD -R and HD DVD-RW uses the land pre-pit system of the DVD-R(W) This computer hardware article is

4408-455: The number of words transmitted to or from an input-output unit in response to a single input-output instruction. Block size is a structural property of an input-output unit; it may have been fixed by the design or left to be varied by the program.     [...] Most important, from the point of view of editing, will be the ability to handle any characters or digits, from 1 to 6 bits long.     Figure 2 shows

4484-414: The outer edge of the disc, for optional high speed calibration. The calibration is necessary to allow for slight manufacturing defects, greatly reducing or completely eliminating rejected discs and drives, reducing costs and eliminating potential waste. The information below describes the different types of recording layers that may be used on BD-R and BD-RE discs. "Normal" BD-R discs use a composite (or, in

4560-460: The physical or logical control of data flow over the transmission media. During the early 1960s, while also active in ASCII standardization, IBM simultaneously introduced in its product line of System/360 the eight-bit Extended Binary Coded Decimal Interchange Code (EBCDIC), an expansion of their six-bit binary-coded decimal (BCDIC) representations used in earlier card punches. The prominence of

4636-427: The pits and lands found on prepressed/prerecorded/replicated discs, BD-R and RE discs contain grooves which contain a wobble frequency that is used to locate the position of the reading or writing laser on the disc. BD-R has an Optimum Power Calibrations (OPC) / Test Zone, which is used to calibrate (finely adjust) the power of the writing laser before and during writing, and it also has a Drive Calibration Zone (DCZ) at

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4712-458: The potential ambiguity of the term "byte". The symbol for octet, 'o', also conveniently eliminates the ambiguity in the symbol 'B' between byte and bel . The term byte was coined by Werner Buchholz in June 1956, during the early design phase for the IBM Stretch computer, which had addressing to the bit and variable field length (VFL) instructions with a byte size encoded in

4788-453: The prefix kilo as 1000 (10 ); other systems are based on powers of 2 . Nomenclature for these systems has led to confusion. Systems based on powers of 10 use standard SI prefixes ( kilo , mega , giga , ...) and their corresponding symbols (k, M, G, ...). Systems based on powers of 2, however, might use binary prefixes ( kibi , mebi , gibi , ...) and their corresponding symbols (Ki, Mi, Gi, ...) or they might use

4864-525: The prefixes K, M, and G, creating ambiguity when the prefixes M or G are used. While the difference between the decimal and binary interpretations is relatively small for the kilobyte (about 2% smaller than the kibibyte), the systems deviate increasingly as units grow larger (the relative deviation grows by 2.4% for each three orders of magnitude). For example, a power-of-10-based terabyte is about 9% smaller than power-of-2-based tebibyte. Definition of prefixes using powers of 10—in which 1 kilobyte (symbol kB)

4940-424: The remaining bits blank. The resultant gaps can be edited out later by programming [...] Wobble frequency Optical discs , with the exception of DVD-RAM , have their data encoded on a single spiral, or a groove , which covers the surface of the disc. In the case of recordable media, this spiral contains a slight sinusoidal deviation from a perfect spiral . The period of this sine curve corresponds to

5016-450: The same term even within a single vendor. These terms include double word , half word , long word , quad word , slab , superword and syllable . There are also informal terms. e.g., half byte and nybble for 4 bits, octal K for 1000 8 . Contemporary computer memory has a binary architecture making a definition of memory units based on powers of 2 most practical. The use of the metric prefix kilo for binary multiples arose as

5092-440: The spare area. Within the "Volume Space", the capacity that can be occupied by the content of files is also slightly reduced by file system overhead and by slack space as well, but the amount of slack space is trivial given that file systems on optical discs use a low cluster size (also referred to as "logical sector size") of 2 KiB (2048 bytes), matching the size of a single physical sector on optical discs. With packet writing ,

5168-535: The term is unclear, but it can be found in British, Dutch, and German sources of the 1960s and 1970s, and throughout the documentation of Philips mainframe computers. The unit symbol for the byte is specified in IEC 80000-13 , IEEE 1541 and the Metric Interchange Format as the upper-case character B. In the International System of Quantities (ISQ), B is also the symbol of the bel ,

5244-724: The twenty-first century. In this era, bit groupings in the instruction stream were often referred to as syllables or slab , before the term byte became common. The modern de facto standard of eight bits, as documented in ISO/IEC 2382-1:1993, is a convenient power of two permitting the binary-encoded values 0 through 255 for one byte, as 2 to the power of 8 is 256. The international standard IEC 80000-13 codified this common meaning. Many types of applications use information representable in eight or fewer bits and processor designers commonly optimize for this usage. The popularity of major commercial computing architectures has aided in

5320-532: The ubiquitous acceptance of the 8-bit byte. Modern architectures typically use 32- or 64-bit words, built of four or eight bytes, respectively. The unit symbol for the byte was designated as the upper-case letter B by the International Electrotechnical Commission (IEC) and Institute of Electrical and Electronics Engineers (IEEE). Internationally, the unit octet explicitly defines a sequence of eight bits, eliminating

5396-425: The usable capacity may differ from the advertised capacity. Seagate was sued on similar grounds and also settled. Many programming languages define the data type byte . The C and C++ programming languages define byte as an "addressable unit of data storage large enough to hold any member of the basic character set of the execution environment" (clause 3.6 of the C standard). The C standard requires that

5472-548: The write will take longer to complete. Erasing a BD-RE is not necessary since existing data can be directly overwritten. Unlike with CD-RW, there is no need for blanking BD-RE before re-use, but they need to be formatted before first use. Burn programs may detect the unformatted state and automatically format the medium before beginning to write. Write verification is a feature of formatted Blu-ray media, officially called "Defect Management". Similar functionality existed on DVD-RAM and on Mount Rainer -supporting disc drives, but BD-R

5548-404: Was advertised as "110 Kbyte", using the 1000 convention. Likewise, the 8-inch DEC RX01 floppy (1975) held 256 256 bytes formatted, and was advertised as "256k". Some devices were advertised using a mixture of the two definitions: most notably, floppy disks advertised as "1.44 MB" have an actual capacity of 1440 KiB , the equivalent of 1.47 MB or 1.41 MiB. In 1995,

5624-523: Was in the context of the input-output equipment of the 1950s, which handled six bits at a time. The possibility of going to 8-bit bytes was considered in August 1956 and incorporated in the design of Stretch shortly thereafter .     The first published reference to the term occurred in 1959 in a paper ' Processing Data in Bits and Pieces ' by G A Blaauw , F P Brooks Jr and W Buchholz in

5700-530: Was jointly developed by Rand , MIT, and IBM. Later on, Schwartz's language JOVIAL actually used the term, but the author recalled vaguely that it was derived from AN/FSQ-31 . Early computers used a variety of four-bit binary-coded decimal (BCD) representations and the six-bit codes for printable graphic patterns common in the U.S. Army ( FIELDATA ) and Navy . These representations included alphanumeric characters and special graphical symbols. These sets were expanded in 1963 to seven bits of coding, called

5776-417: Was working on IBM's Project Stretch in the mid 1950s. His letter tells the story.     Not being a regular reader of your magazine, I heard about the question in the November 1976 issue regarding the origin of the term "byte" from a colleague who knew that I had perpetrated this piece of jargon [see page 77 of November 1976 BYTE, "Olde Englishe"] . I searched my files and could not locate

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