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ZX80 Character Set
The ZX80 character set is the character encoding used by the Sinclair Research ZX80 microcomputer with its original 4K BASIC ROM. The encoding uses one byte per character for 256 code points. It has no relationship with previously established ones like ASCII or EBCDIC, but it is related though not identical to the character set of the successor ZX81. Printable characters The character set has 64 unique glyphs present at code points 0–63. With the most significant bit set the character is generated in inverse video; corresponding to code points 128–191. These 128 values are the only displayable ones allowed in the video memory (known as the display file). The remaining code points (64–127 and 192–255) are used as control characters or Sinclair BASIC keywords, while some are unused. The small effective range of only 64 unique glyphs precludes support for Latin lower case letters, and many symbols used widely in computing such as the exclamation point or the at sign. Ther ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
At Sign
The at sign, , is normally read aloud as "at"; it is also commonly called the at symbol, commercial at, or address sign. It is used as an accounting and invoice abbreviation meaning "at a rate of" (e.g. 7 widgets @ £2 per widget = £14), but it is now seen more widely in email addresses and social media platform handles. The absence of a single English word for the symbol has prompted some writers to use the French ''arobase'' or Spanish and Portuguese ''arroba'', or to coin new words such as ''ampersat'' and ''asperand'', or the (visual) onomatopoeia ''strudel'', but none of these have achieved wide use. Although not included on the keyboard of the earliest commercially successful typewriters, it was on at least one 1889 model"The @-symbol, part 2 of 2" , [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quotation Mark
Quotation marks (also known as quotes, quote marks, speech marks, inverted commas, or talking marks) are punctuation marks used in pairs in various writing systems to set off direct speech, a quotation, or a phrase. The pair consists of an opening quotation mark and a closing quotation mark, which may or may not be the same character. Quotation marks have a variety of forms in different languages and in different media. History The single quotation mark is traced to Ancient Greek practice, adopted and adapted by monastic copyists. Isidore of Seville, in his seventh century encyclopedia, , described their use of the Greek ''diplé'' (a chevron): 3⟩ Diplé. Our copyists place this sign in the books of the people of the Church, to separate or to indicate the quotations drawn from the Holy Scriptures. The double quotation mark derives from a marginal notation used in fifteenth-century manuscript annotations to indicate a passage of particular importance (not necessar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Character
In computer programming, whitespace is any character or series of characters that represent horizontal or vertical space in typography. When rendered, a whitespace character does not correspond to a visible mark, but typically does occupy an area on a page. For example, the common whitespace symbol (also ASCII 32) represents a blank space punctuation character in text, used as a word divider in Western scripts. Overview With many keyboard layouts, a whitespace character may be entered by pressing . Horizontal whitespace may also be entered on many keyboards with the key, although the length of the space may vary. Vertical whitespace may be input by typing , which creates a 'newline' code sequence in most programs. On older keyboards, this key may instead be labeled , a holdover from typewriter keyboards' carriage return keys, which generated an electromechanical return to the left stop (Unicode character ) and a move to the next line (). Many early computer games used whitesp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ZX Spectrum Character Set
The ZX Spectrum character set is the variant of ASCII used in the ZX Spectrum family computers. It is based on ASCII-1967 but the characters ^, ` and DEL are replaced with ↑, £ and ©. It also differs in its use of the C0 control codes other than the common BS and CR, and it makes use of the 128 high-bit characters beyond the ASCII range.ZX Spectrum manual, Appendix A, the character set The ZX Spectrum's main set of printable characters and system font are also used by the Jupiter Ace computer. Printable characters Standard US-ASCII, 0x20–0x7F, is included in the Spectrum character set except that code point 0x5E is an up-arrow (↑) instead of a caret (^), 0x60 is the pound sign (£) instead of the grave accent (`), and 0x7F is the copyright sign (©) instead of the control character DEL. Note that the use of 0x5E as ↑ was also the case in the older 1963 version of ASCII. The £ sign was not mapped to 0x23 as in the British variant of ASCII ( ISO-646-GB), allowing bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinclair ZX Spectrum
The ZX Spectrum () is an 8-bit home computer that was developed by Sinclair Research. It was released in the United Kingdom on 23 April 1982, and became Britain's best-selling microcomputer. Referred to during development as the ''ZX81 Colour'' and ''ZX82'', it was launched as the ''ZX Spectrum'' to highlight the machine's colour display, which differed from the black and white display of its predecessor, the ZX81. The Spectrum was released as six different models, ranging from the entry level with 16 KB RAM released in 1982 to the ZX Spectrum +3 with 128 KB RAM and built in floppy disk drive in 1987; altogether they sold over 5 million units worldwide (not counting unofficial clones). The Spectrum was among the first home computers in the United Kingdom aimed at a mainstream audience, and it thus had similar significance to the Commodore 64 in the US and the Thomson MO5 in France. The introduction of the ZX Spectrum led to a boom in companies producing software an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ZX81
The ZX81 is a home computer that was produced by Sinclair Research and manufactured in Dundee, Scotland, by Timex Corporation. It was launched in the United Kingdom in March 1981 as the successor to Sinclair's ZX80 and designed to be a low-cost introduction to home computing for the general public. It was hugely successful; more than 1.5 million units were sold. In the United States it was initially sold as the ZX-81 under licence by Timex. Timex later produced its own versions of the ZX81: the Timex Sinclair 1000 and Timex Sinclair 1500. Unauthorized ZX81 clones were produced in several countries. The ZX81 was designed to be small, simple, and above all, inexpensive, with as few components as possible. Video output is to a television set rather than a dedicated monitor. Programs and data are loaded and saved onto compact audio cassettes. It uses only four silicon chips and a mere 1 KB of memory. It has no power switch or moving parts, with the exception of a VHF ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Read-only Memory
Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM cannot be electronically modified after the manufacture of the memory device. Read-only memory is useful for storing software that is rarely changed during the life of the system, also known as firmware. Software applications (like video games) for programmable devices can be distributed as plug-in cartridges containing ROM. Strictly speaking, ''read-only memory'' refers to memory that is hard-wired, such as diode matrix or a mask ROM integrated circuit (IC), which cannot be electronically changed after manufacture. Although discrete circuits can be altered in principle, through the addition of bodge wires and/or the removal or replacement of components, ICs cannot. Correction of errors, or updates to the software, require new devices to be manufactured and to replace the installed device. Floating-gate ROM semiconductor memory in the form of erasab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
String (computer Science)
In computer programming, a string is traditionally a sequence of characters, either as a literal constant or as some kind of variable. The latter may allow its elements to be mutated and the length changed, or it may be fixed (after creation). A string is generally considered as a data type and is often implemented as an array data structure of bytes (or words) that stores a sequence of elements, typically characters, using some character encoding. ''String'' may also denote more general arrays or other sequence (or list) data types and structures. Depending on the programming language and precise data type used, a variable declared to be a string may either cause storage in memory to be statically allocated for a predetermined maximum length or employ dynamic allocation to allow it to hold a variable number of elements. When a string appears literally in source code, it is known as a string literal or an anonymous string. In formal languages, which are used in mathematical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unicode Block
A Unicode block is one of several contiguous ranges of numeric character codes (code points) of the Unicode character set that are defined by the Unicode Consortium for administrative and documentation purposes. Typically, proposals such as the addition of new glyphs are discussed and evaluated by considering the relevant block or blocks as a whole. Each block is generally, but not always, meant to supply glyphs used by one or more specific languages, or in some general application area such as mathematics, surveying, decorative typesetting, social forums, etc. Design and implementation Unicode blocks are identified by unique names, which use only ASCII characters and are usually descriptive of the nature of the symbols, in English; such as "Tibetan" or "Supplemental Arrows-A". (When comparing block names, one is supposed to equate uppercase with lowercase letters, and ignore any whitespace, hyphens, and underbars; so the last name is equivalent to "supplemental_arrows__a" and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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