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Commodore 1581
The Commodore 1581 is a 3½-inch double-sided double-density floppy disk drive that was released by Commodore Business Machines (CBM) in 1987, primarily for its C64 and C128 home/personal computers. The drive stores 800 kilobytes using an MFM encoding but formats different from the MS-DOS (720 kB), Amiga (880 kB), and Mac Plus (800 kB) formats. With special software it's possible to read C1581 disks on an x86 PC system, and likewise, read MS-DOS and other formats of disks in the C1581 (using Big Blue Reader), provided that the PC or other floppy handles the size format. This capability was most frequently used to read MS-DOS disks. The drive was released in the summer of 1987 and quickly became popular with bulletin board system (BBS) operators and other users. Like the 1541 and 1571, the 1581 has an onboard MOS Technology 6502 CPU with its own ROM and RAM, and uses a serial version of the IEEE-488 interface. Inexplicably, the drive's ROM contains commands for parallel u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commodore 64
The Commodore 64, also known as the C64, is an 8-bit home computer introduced in January 1982 by Commodore International (first shown at the Consumer Electronics Show, January 7–10, 1982, in Las Vegas). It has been listed in the Guinness World Records as the highest-selling single computer model of all time, with independent estimates placing the number sold between 12.5 and 17 million units. Volume production started in early 1982, marketing in August for . Preceded by the VIC-20 and Commodore PET, the C64 took its name from its of RAM. With support for multicolor sprites and a custom chip for waveform generation, the C64 could create superior visuals and audio compared to systems without such custom hardware. The C64 dominated the low-end computer market (except in the UK and Japan, lasting only about six months in Japan) for most of the later years of the 1980s. For a substantial period (1983–1986), the C64 had between 30% and 40% share of the US market and two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Floppy Disk
A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined with a fabric that removes dust particles from the spinning disk. Floppy disks store digital data which can be read and written when the disk is inserted into a floppy disk drive (FDD) connected to or inside a computer or other device. The first floppy disks, invented and made by IBM, had a disk diameter of . Subsequently, the 5¼-inch and then the 3½-inch became a ubiquitous form of data storage and transfer into the first years of the 21st century. 3½-inch floppy disks can still be used with an external USB floppy disk drive. USB drives for 5¼-inch, 8-inch, and other-size floppy disks are rare to non-existent. Some individuals and organizations continue to use older equipment to read or transfer data from floppy disks. Floppy di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amiga
Amiga is a family of personal computers introduced by Commodore International, Commodore in 1985. The original model is one of a number of mid-1980s computers with 16- or 32-bit processors, 256 KB or more of RAM, mouse-based GUIs, and significantly improved graphics and audio compared to previous 8-bit systems. This includes the Atari ST—released earlier the same year—as well as the Macintosh and Acorn Archimedes. Based on the Motorola 68000 microprocessor, the Amiga differs from its contemporaries through the inclusion of custom hardware to accelerate graphics and sound, including sprite (computer graphics), sprites and a blitter, and a pre-emptive multitasking operating system called AmigaOS. The Amiga 1000 was released in July 1985, but production problems kept it from becoming widely available until early 1986. The best-selling model, the Amiga 500, was introduced in 1987 along with the more expandable Amiga 2000. The Amiga 3000 was introduced in 1990, followed by t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Job Queue
In system software, a job queue ( batch queue, input queue), is a data structure maintained by job scheduler software containing jobs to run. Users submit their programs that they want executed, "jobs", to the queue for batch processing. The scheduler software maintains the queue as the pool of jobs available for it to run. Multiple batch queues might be used by the scheduler to differentiate types of jobs depending on parameters such as: * job priority * estimated execution time * resource requirements The use of a batch queue gives these benefits: * sharing of computer resources among many users * time-shifts job processing to when the computer is less busy * avoids idling the compute resources without minute-by-minute human supervision * allows around-the-clock high utilization of expensive computing resources Any process that comes to the CPU should wait in a queue. See also *Command pattern * Command queue *Job scheduler *Priority queue In computer science, a pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extra-high Density
A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined with a fabric that removes dust particles from the spinning disk. Floppy disks store digital data which can be read and written when the disk is inserted into a floppy disk drive (FDD) connected to or inside a computer or other device. The first floppy disks, invented and made by IBM, had a disk diameter of . Subsequently, the 5¼-inch and then the 3½-inch became a ubiquitous form of data storage and transfer into the first years of the 21st century. 3½-inch floppy disks can still be used with an external USB floppy disk drive. USB drives for 5¼-inch, 8-inch, and other-size floppy disks are rare to non-existent. Some individuals and organizations continue to use older equipment to read or transfer data from floppy disks. Floppy disks w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CMD FD-4000
The CMD FD series was Creative Micro Designs (CMD)'s range of third-party floppy disk drives for the Commodore 8-bit line of home computers. Using 3½" floppy disks, they provided a significantly larger storage capacity than Commodore-produced drives; the FD-2000 offered 1600 kB of storage using standard double-sided, high-density floppies, while the FD-4000 also allowed the use of 3200 kB extra-high density (ED) floppies. In contrast, the Commodore 1581 3½" drive only supported 800 kB double-sided, double-density disks. Features In addition to the higher storage capacity, the FD series also provided additional features not found on the Commodore 1581. A "SWAP" button on the front panel allowed the drive number to be easily switched with that of another Commodore drive on the serial bus, without the need to enter any commands into the computer. It also provided a "1541 emulation mode", allowing partitions on a 3½" disk to simulate the behavior of a 5¼" Commodore 1541 floppy. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High Density
Disk density is a capacity designation on magnetic storage, usually floppy disks. Each designation describes a set of characteristics that can affect the areal density of a disk or the efficiency of the encoded data. Such characteristics include modulation method, track width, coercivity, and magnetic field direction. 8-inch media ''Single density'' (SD or 1D) describes the first generation of floppy disks that use an iron oxide coating. Floppy drives utilize 300-oersted write heads, FM encoding, and a track width of for a density of 48 tracks-per-inch (tpi) and 5876 bits-per-inch (bpi). ''Double density'' (DD or 2D) doubles capacity over SD by replacing FM encoding with an improved line code, such as modified frequency modulation (MFM), modified modified frequency modulation (M²FM), FM/MFM or group coded recording (GCR). 5¼-inch media ''SD'' (''1D'') and ''DD'' (''2D'') designations were generally identical to those of 8-inch disks. ''Quad density'' (QD or 4D) doubl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CMD FD-2000
The CMD FD series was Creative Micro Designs (CMD)'s range of third-party floppy disk drives for the Commodore 8-bit line of home computers. Using 3½" floppy disks, they provided a significantly larger storage capacity than Commodore-produced drives; the FD-2000 offered 1600 kB of storage using standard double-sided, high-density floppies, while the FD-4000 also allowed the use of 3200 kB extra-high density (ED) floppies. In contrast, the Commodore 1581 3½" drive only supported 800 kB double-sided, double-density disks. Features In addition to the higher storage capacity, the FD series also provided additional features not found on the Commodore 1581. A "SWAP" button on the front panel allowed the drive number to be easily switched with that of another Commodore drive on the serial bus, without the need to enter any commands into the computer. It also provided a "1541 emulation mode", allowing partitions on a 3½" disk to simulate the behavior of a 5¼" Commodore 1541 floppy. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Creative Micro Designs
Creative Micro Designs (CMD) was founded in 1987 by Doug Cotton and Mark Fellows. It is a computer technology company which originally developed and sold products for the Commodore 64 and C128 8-bit personal computers. After 2001 it sold PCs and related equipment. History CMD's first product, JiffyDOS, was developed from 1985 onwards by Mark Fellows. An updated disk operating system, it maintained broad compatibility with Commodore floppy drives' DOS while offering much increased read write access. CMD stopped selling Commodore products in 2001. In July of that year, programmer Maurice Randal was sold an exclusive license to produce and sell the Commodore related products. His company Click Here Software Co supplied the products until around 2009. In 2010, Jim Brain acquired the license to supply JiffyDOS. Since January of that year, he has sold the product via his web shop Retro Innovations. Products * SuperCPU - A 65816 CPU 8/16-bit upgrade for the C64 and C128 re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Byte
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 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 () 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 the bit endianness. The first bit is number 0, making the eighth bit number 7. 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 wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Directory (computing)
In computing, a directory is a file system cataloging structure which contains references to other computer files, and possibly other directories. On many computers, directories are known as folders, or drawers, analogous to a workbench or the traditional office filing cabinet. The name derives from books like a telephone directory that lists the phone numbers of all the people living in a certain area. Files are organized by storing related files in the same directory. In a hierarchical file system (that is, one in which files and directories are organized in a manner that resembles a tree), a directory contained inside another directory is called a subdirectory. The terms parent and child are often used to describe the relationship between a subdirectory and the directory in which it is cataloged, the latter being the parent. The top-most directory in such a filesystem, which does not have a parent of its own, is called the root directory. Overview Historically, and even o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disk Partitioning
Disk partitioning or disk slicing is the creation of one or more regions on secondary storage, so that each region can be managed separately. These regions are called partitions. It is typically the first step of preparing a newly installed disk, before any file system is created. The disk stores the information about the partitions' locations and sizes in an area known as the partition table that the operating system reads before any other part of the disk. Each partition then appears to the operating system as a distinct "logical" disk that uses part of the actual disk. System administrators use a program called a partition editor to create, resize, delete, and manipulate the partitions. Partitioning allows the use of different filesystems to be installed for different kinds of files. Separating user data from system data can prevent the system partition from becoming full and rendering the system unusable. Partitioning can also make backing up easier. A disadvantage is that i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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