A CD-ROM is a pre-pressed optical compact disc that contains data. Computers can read—but not write to or erase—CD-ROMs, i.e. it is a type of read-only memory. During the 1990s, CD-ROMs were popularly used to distribute software and data for computers and fourth generation video game consoles; some CDs, called enhanced CDs, hold both computer data and audio with the latter capable of being played on a CD player, while data is only usable on a computer. The CD-ROM format was developed by Japanese company Denon in 1982, it was an extension of Compact Disc Digital Audio, adapted the format to hold any form of digital data, with a storage capacity of 553 MiB. CD-ROM was introduced by Denon and Sony at a Japanese computer show in 1984; the Yellow Book is the technical standard. One of a set of color-bound books that contain the technical specifications for all CD formats, the Yellow Book, standardized by Sony and Philips in 1983, specifies a format for discs with a maximum capacity of 650 MiB. CD-ROMs are identical in appearance to audio CDs, data are stored and retrieved in a similar manner.
Discs are made from a 1.2 mm thick disc of polycarbonate plastic, with a thin layer of aluminium to make a reflective surface. The most common size of CD-ROM is 120 mm in diameter, though the smaller Mini CD standard with an 80 mm diameter, as well as shaped compact discs in numerous non-standard sizes and molds, are available. Data is stored on the disc as a series of microscopic indentations. A laser is shone onto the reflective surface of the disc to read the pattern of lands; because the depth of the pits is one-quarter to one-sixth of the wavelength of the laser light used to read the disc, the reflected beam's phase is shifted in relation to the incoming beam, causing destructive interference and reducing the reflected beam's intensity. This is converted into binary data. Several formats are used for data stored on compact discs, known as the Rainbow Books; the Yellow Book, published in 1988, defines the specifications for CD-ROMs, standardized in 1989 as the ISO/IEC 10149 / ECMA-130 standard.
The CD-ROM standard builds on top of the original Red Book CD-DA standard for CD audio. Other standards, such as the White Book for Video CDs, further define formats based on the CD-ROM specifications; the Yellow Book itself is not available, but the standards with the corresponding content can be downloaded for free from ISO or ECMA. There are several standards that define how to structure data files on a CD-ROM. ISO 9660 defines the standard file system for a CD-ROM. ISO 13490 is an improvement on this standard which adds support for non-sequential write-once and re-writeable discs such as CD-R and CD-RW, as well as multiple sessions; the ISO 13346 standard was designed to address most of the shortcomings of ISO 9660, a subset of it evolved into the UDF format, adopted for DVDs. The bootable CD specification was issued in January 1995, to make a CD emulate a hard disk or floppy disk, is called El Torito. Data stored on CD-ROMs follows the standard CD data encoding techniques described in the Red Book specification.
This includes cross-interleaved Reed–Solomon coding, eight-to-fourteen modulation, the use of pits and lands for coding the bits into the physical surface of the CD. The structures used to group data on a CD-ROM are derived from the Red Book. Like audio CDs, a CD-ROM sector contains 2,352 bytes of user data, composed of 98 frames, each consisting of 33-bytes. Unlike audio CDs, the data stored in these sectors corresponds to any type of digital data, not audio samples encoded according to the audio CD specification. To structure and protect this data, the CD-ROM standard further defines two sector modes, Mode 1 and Mode 2, which describe two different layouts for the data inside a sector. A track inside a CD-ROM only contains sectors in the same mode, but if multiple tracks are present in a CD-ROM, each track can have its sectors in a different mode from the rest of the tracks, they can coexist with audio CD tracks as well, the case of mixed mode CDs. Both Mode 1 and 2 sectors use the first 16 bytes for header information, but differ in the remaining 2,336 bytes due to the use of error correction bytes.
Unlike an audio CD, a CD-ROM cannot rely on error concealment by interpolation. To achieve improved error correction and detection, Mode 1, used for digital data, adds a 32-bit cyclic redundancy check code for error detection, a third layer of Reed–Solomon error correction using a Reed-Solomon Product-like Code. Mode 1 therefore contains 288 bytes per sector for error detection and correction, leaving 2,048 bytes per sector available for data. Mode 2, more appropriate for image or video data, contains no additional error detection or correction bytes, having therefore 2,336 available data bytes per sector. Note that both modes, like audio CDs, still benefit from the lower layers of error correction at the frame level. Before being stored on a disc with the techniques described above, each CD-ROM sector is scrambled to prevent some problematic patterns from showing up; these scrambled sectors follow the same encoding process described in the Red Book in order to be stored
A floppy disk known as a floppy, diskette, or disk, is a type of disk storage composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic enclosure lined with fabric that removes dust particles. Floppy disks are written by a floppy disk drive. Floppy disks as 8-inch media and in 5 1⁄4-inch and 3 1⁄2 inch sizes, were a ubiquitous form of data storage and exchange from the mid-1970s into the first years of the 21st century. By 2006 computers were manufactured with installed floppy disk drives; these formats are handled by older equipment. The prevalence of floppy disks in late-twentieth century culture was such that many electronic and software programs still use the floppy disks as save icons. While floppy disk drives still have some limited uses with legacy industrial computer equipment, they have been superseded by data storage methods with much greater capacity, such as USB flash drives, flash storage cards, portable external hard disk drives, optical discs, cloud storage and storage available through computer networks.
The first commercial floppy disks, developed in the late 1960s, were 8 inches in diameter. These disks and associated drives were produced and improved upon by IBM and other companies such as Memorex, Shugart Associates, Burroughs Corporation; the term "floppy disk" appeared in print as early as 1970, although IBM announced its first media as the "Type 1 Diskette" in 1973, the industry continued to use the terms "floppy disk" or "floppy". In 1976, Shugart Associates introduced the 5 1⁄4-inch FDD. By 1978 there were more than 10 manufacturers producing such FDDs. There were competing floppy disk formats, with hard- and soft-sector versions and encoding schemes such as FM, MFM, M2FM and GCR; the 5 1⁄4-inch format displaced the 8-inch one for most applications, the hard-sectored disk format disappeared. The most common capacity of the 5 1⁄4-inch format in DOS-based PCs was 360 KB, for the DSDD format using MFM encoding. In 1984 IBM introduced with its PC-AT model the 1.2 MB dual-sided 5 1⁄4-inch floppy disk, but it never became popular.
IBM started using the 720 KB double-density 3 1⁄2-inch microfloppy disk on its Convertible laptop computer in 1986 and the 1.44 MB high-density version with the PS/2 line in 1987. These disk drives could be added to older PC models. In 1988 IBM introduced a drive for 2.88 MB "DSED" diskettes in its top-of-the-line PS/2 models, but this was a commercial failure. Throughout the early 1980s, limitations of the 5 1⁄4-inch format became clear. Designed to be more practical than the 8-inch format, it was itself too large. A number of solutions were developed, with drives at 2-, 2 1⁄2-, 3-, 3 1⁄4-, 3 1⁄2- and 4-inches offered by various companies, they all shared a number of advantages over the old format, including a rigid case with a sliding metal shutter over the head slot, which helped protect the delicate magnetic medium from dust and damage, a sliding write protection tab, far more convenient than the adhesive tabs used with earlier disks. The large market share of the well-established 5 1⁄4-inch format made it difficult for these diverse mutually-incompatible new formats to gain significant market share.
A variant on the Sony design, introduced in 1982 by a large number of manufacturers, was rapidly adopted. The term floppy disk persisted though style floppy disks have a rigid case around an internal floppy disk. By the end of the 1980s, 5 1⁄4-inch disks had been superseded by 3 1⁄2-inch disks. During this time, PCs came equipped with drives of both sizes. By the mid-1990s, 5 1⁄4-inch drives had disappeared, as the 3 1⁄2-inch disk became the predominant floppy disk; the advantages of the 3 1⁄2-inch disk were its higher capacity, its smaller size, its rigid case which provided better protection from dirt and other environmental risks. If a person touches the exposed disk surface of a 5 1⁄4-inch disk through the drive hole, fingerprints may foul the disk—and the disk drive head if the disk is subsequently loaded into a drive—and it is easily possible to damage a disk of this type by folding or creasing it rendering it at least unreadable; however due to its simpler construction the 5 1⁄4-inch disk unit price was lower throughout its history in the range of a third to a half that of a 3 1⁄2-inch disk.
Floppy disks became commonplace during the 1980s and 1990s in their use with personal computers to distribute software, transfer data, create backups. Before hard disks became affordable to the general population, floppy disks were used to store a computer's operating system. Most home computers from that period have an elementary OS and BASIC stored in ROM, with the option of loading a more advanced operating system from a floppy disk. By the early 1990s, the increasing software size meant large packages like Windows or Adobe Photoshop required a dozen disks or more. In 1996, there were an estimated five billion standard floppy disks in use. Distribution of larger packages was replaced by CD-ROMs, DVDs and online distribution. An
Bankruptcy is a legal process through which people or other entities who cannot repay debts to creditors may seek relief from some or all of their debts. In most jurisdictions, bankruptcy is imposed by a court order initiated by the debtor. Bankruptcy is not the only legal status that an insolvent person may have, the term bankruptcy is therefore not a synonym for insolvency. In some countries, such as the United Kingdom, bankruptcy is limited to individuals. In the United States, bankruptcy is applied more broadly to formal insolvency proceedings. In France, the cognate French word banqueroute is used for cases of fraudulent bankruptcy, whereas the term faillite is used for bankruptcy in accordance with the law; the word bankruptcy is derived from Italian banca rotta, meaning "broken bench", which may stem from a widespread custom in the Republic of Genoa of breaking a moneychanger's bench or counter to signify their insolvency, or which may be only a figure of speech. In Ancient Greece, bankruptcy did not exist.
If a man owed and he could not pay, he and his wife, children or servants were forced into "debt slavery", until the creditor recouped losses through their physical labour. Many city-states in ancient Greece limited debt slavery to a period of five years. However, servants of the debtor could be retained beyond that deadline by the creditor and were forced to serve their new lord for a lifetime under harsher conditions. An exception to this rule was Athens; the Statute of Bankrupts of 1542 was the first statute under English law dealing with bankruptcy or insolvency. Bankruptcy is documented in East Asia. According to al-Maqrizi, the Yassa of Genghis Khan contained a provision that mandated the death penalty for anyone who became bankrupt three times. A failure of a nation to meet bond repayments has been seen on many occasions. Philip II of Spain had to declare four state bankruptcies in 1557, 1560, 1575 and 1596. According to Kenneth S. Rogoff, "Although the development of international capital markets was quite limited prior to 1800, we catalog the various defaults of France, Prussia and the early Italian city-states.
At the edge of Europe, Egypt and Turkey have histories of chronic default as well." The principal focus of modern insolvency legislation and business debt restructuring practices no longer rests on the elimination of insolvent entities, but on the remodeling of the financial and organizational structure of debtors experiencing financial distress so as to permit the rehabilitation and continuation of the business. For private households, some argue that it is insufficient to dismiss debts after a certain period, it is important to assess the underlying problems and to minimize the risk of financial distress to re-occur. It has been stressed that debt advice, a supervised rehabilitation period, financial education and social help to find sources of income and to improve the management of household expenditures must be provided during this period of rehabilitation. In most EU Member States, debt discharge is conditioned by a partial payment obligation and by a number of requirements concerning the debtor's behavior.
In the United States, discharge is conditioned to a lesser extent. The spectrum is broad in the EU, with the UK coming closest to the US system; the Other Member States do not provide the option of a debt discharge. Spain, for example, passed a bankruptcy law in 2003 which provides for debt settlement plans that can result in a reduction of the debt or an extension of the payment period of maximally five years, but it does not foresee debt discharge. In the US, it is difficult to discharge federal or federally guaranteed student loan debt by filing bankruptcy. Unlike most other debts, those student loans may be discharged only if the person seeking discharge establishes specific grounds for discharge under the Brunner test, under which the court evaluates three factors: If required to repay the loan, the borrower cannot maintain a minimal standard of living. If a debtor proves all three elements, a court may permit only a partial discharge of the student loan. Student loan borrowers may benefit from restructuring their payments through a Chapter 13 bankruptcy repayment plan, but few qualify for discharge of part or all of their student loan debt.
Bankruptcy fraud is a white-collar crime. While difficult to generalize across jurisdictions, common criminal acts under bankruptcy statutes involve concealment of assets, concealment or destruction of documents, conflicts of interest, fraudulent claims, false statements or declarations, fee fixing or redistribution arrangements. Falsifications on bankruptcy forms constitute perjury. Multiple filings are not in and of themselves criminal, but they may violate provisions of bankruptcy law. In the U. S. bankruptcy fraud statutes are focused on the mental state of particular actions. Bankruptcy fraud is a federal crime in the United States. Bankruptcy fraud should be distinguished from strategic bankruptcy, not a criminal act since it creates a real bankruptcy state. Howeve
Not to be confused with SuperDrive, a trademark used by Apple Computer for various disk drive products or the Super Disc, CD addon for the Super Nintendo Entertainment System. The SuperDisk LS-120 is a high-capacity alternative to the 90 mm, 1.44 MB floppy disk. The SuperDisk hardware was created by 3M's storage products group Imation in 1997, with manufacturing chiefly by Matsushita; the SuperDisk had little success in North America. It was more successful in Asia and Australia, where the second-generation SuperDisk LS-240 drive and disk was released. SuperDisk worldwide ceased manufacturing in 2003; the design of the SuperDisk system came from an early 1990s project at Iomega. It is one of the last examples of floptical technology, where lasers are used to guide a magnetic head, much smaller than those used in traditional floppy disk drives. Iomega orphaned the project around the time they decided to release the Zip drive in 1994; the idea ended up at 3M, where the concept was refined and the design was licensed to established floppy drive makers Matsushita and Mitsubishi.
Other companies involved in the development of SuperDisk include OR Technology. Matsushita continued development of the technology and released the LS-240, it has double the capacity and the added feature of being able to format regular floppy disks to 32 MB capacity. However, this higher density comes at a price – the entire disk must be rewritten any time a change is made, much like early CD-RW media. A SuperDisk drive was used in two Panasonic digital cameras, the PV-SD4090 and PV-SD5000, which allowed them to use both SuperDisk and 3.5" floppy disks as the memory media. The SuperDisk's format was designed to supersede the floppy disk with its higher-capacity media that imitated the ubiquitous format with its own 120 MB disk storage while the SuperDisk drive itself was backwards compatible with 1.44 MB and 720 KB floppy formats. Superdisk drives read and write faster to these sorts of disks than conventional 1.44 MB or 720 KB floppy drives. The newer LS-240 drives have the ability to read and write regular 1.44 MB floppies at much higher densities.
The true capacity of these "SD120MB" drives is 120.375 MiB aka 126.22 MB. The "SD240MB" drives have a capacity of 229.25 MiB aka 240.39 MB. 1.44 MB HD floppies formatted to 32 MB as "FD32MB" in the LS-240 show a dummy FAT12 file system when inserted into a normal floppy drive. SuperDisk drives have been sold in parallel port, USB, SCSI variants. All drives can read and write 1.44 MB and 720 KiB MFM floppies, as used on PCs, Apple Macintoshes, many workstations. 2.88 MB floppy formats are not supported. Imation released a version of the SuperDisk with "Secured Encryption Technology", which uses Blowfish with a 64-bit key to encrypt the contents. Macintosh users found trouble making SuperDisk drives work with the GCR 800 KB or 400 KB diskettes used by older Macintoshes; these disks could be used in a SuperDisk drive only if formatted to PC 720 KB MFM format. Note that no other USB floppy drives supported Mac GCR floppies; the biggest hurdle standing in the way of success was that Iomega's Zip drive had been out for three years when SuperDisk had been released.
Zip had enough popularity to leave the public uninterested in SuperDisk, despite its superior design and its compatibility with the standard floppy disk. By 2000, the entire removable magnetic disk category was obsoleted by the falling prices of CD-R and CD-RW drives, on solid-state. Over the next few years, SuperDisk was discontinued in areas where it was popular. Today, disks are hard to find. Under Windows XP, a USB SuperDisk drive will appear as a 3.5" floppy disk drive, receiving either the drive letter A: or B:. This enables use by software that expects a floppy drive when 1.44 720 KB disks are inserted. 120 MB and 240 MB disks are accessed via A: or B:. The USB models were quite popular for debugging and installing servers that did not have a CD drive available, they could both store massive numbers of drivers for installation purposes as well as be used to run live operating systems, such as ReactOS, which amounts to 150 MB. Floptical Sony HiFD Zip drive Caleb UHD144
The Zip drive is a removable floppy disk storage system, introduced by Iomega in late 1994. Considered medium-to-high-capacity at the time of its release, Zip disks were launched with capacities of 100 MB 250 MB, 750 MB; the format became the most popular of the superfloppy products which filled a niche market in the late 1990s portable storage market. However, it was never popular enough to replace the 3 1⁄2-inch floppy disk; the final versions of the disk reached 750 MB, the capacity available on rewritable CDs, far surpassed by the rewritable DVDs. USB flash drives proved to be the most popular rewritable storage medium among the general public due to the near-ubiquity of USB ports on personal computers and soon after because of the far greater storage sizes offered. Zip drives fell out of favor for mass portable storage during the early 2000s; the Zip brand covered internal and external CD writers known as Zip-650 or Zip-CD, which have no relation to the Zip drive. The Zip drive is a superfloppy disk drive that has all of the 3 1⁄2-inch floppy drive's convenience, but with much greater capacity options and with performance, much improved over a standard floppy drive.
However, Zip disk housings are much thicker than those of floppy disks. In the Zip drive, the heads fly in a manner similar to a hard disk drive. A linear actuator uses the voice coil actuation technology related to modern hard disk drives; the Zip disk uses smaller media, a simplified drive design that reduced its overall cost. The original Zip drive has a maximum data transfer rate of about 1.4 megabyte/second and a seek time of 28 milliseconds on average, compared to a standard 1.44 MB floppy's effective ~16 kB/sec and ~200 ms average seek time. Typical desktop hard disk drives from mid-to-late 1990s revolve at 5,400 rpm and have transfer rates from 3 MB/s to 10 MB/s or more, average seek times from 20 ms to 14 ms or less. Much like hard drives, floppies themselves, the capacity stated for Zip discs is purely nominal, not accounting for any formatting or filestructure overheads, is stated using metric, rather than binary quantifiers. For example, the typical user file capacity of an MS-DOS formatted Zip100 is around 95.4 MiB, or just over 100,000,000 bytes.
This is a lower proportion than the 1.39 MiB available on a "1.44 MB" 3 1⁄2-inch floppy diskette, though it is better than the relationship between that useful capacity and the "2 MB" claimed by an unformatted DSHD. Early-generation Zip drives were in direct competition with the SuperDisk or LS-120 drives, which hold 20% more data and can read standard 3 1⁄2-inch 1.44 MB diskettes, but they have a lower data-transfer rate due to lower rotational speed. The rivalry was over before the dawn of the USB era; the Zip drive was Iomega's third generation of products different from Iomega's earlier Bernoulli Boxes in many ways including the absence of the Bernoulli plate of the earlier products. Zip drives were produced in multiple interfaces including: IDE True ATA ATAPI USB 1.1 USB 2.0 IEEE 1284 with Printer passthrough IEEE 1394 SCSI "Plus". Parallel port external Zip drives are SCSI drives with an integrated Parallel-to-SCSI controller, meaning a true SCSI bus implementation but without the electrical buffering circuits necessary for connecting other external devices.
Early Zip 100 drives use an AIC 7110 SCSI controller and parallel drives used what was known as Iomega MatchMaker. The drives are identified by the operating system as "IMG VP0" and "IMG VP1" respectively. Early external SCSI-based Zip drives were packaged with an included SCSI adapter known as Zip Zoom; the Zip Zoom is a relabeled ISA Adaptec SCSI host controller. Sold separately was a PCMCIA-to-SCSI adapter for laptop compatibility a relabeled Adaptec. Interface availability: Driver support: DOS Microsoft Windows family Some Linux / BSD etc. Oracle Solaris 8, 9, 10, 11 IBM OS/2 Macintosh System 6.x, 7.1–7.5, Mac OS 7.6–9.2 Mac OS X AmigaOS 3.5 or higher IRIX 6.4 or higher NB 1: Requires a driver older than 5.x. Higher-capacity Zip disks must be used in a drive with at least the same capacity ability. Higher-capacity drives can read lower-capacity media; the 250 MB drive writes much more to 100 MB disks than the 100 MB drive, the Iomega software is unable to perform a "long" format on a 100 MB disk.
The 750 MB drive has read-only support for 100 MB disks. The retroreflective spot differs between the 100 MB disk and the 250 MB
Floptical refers to a type of floppy disk drive that combines magnetic and optical technologies to store data on media similar to standard 3 1⁄2-inch floppy disks. The name is a portmanteau of the words "floppy" and "optical", it refers to one brand of drive and disk system, but is used more generically to refer to any system using similar techniques. The original Floptical technology was announced in 1988 and introduced late in 1991 by Insite Peripherals, a venture funded company set up by Jim Adkisson, one of the key engineers behind the original 5 1⁄4-inch floppy disk drive development at Shugart Associates in 1976; the main shareholders were Maxell, Iomega and 3M. The technology involves reading and writing data magnetically, while optically aligning the read/write head in the drive using grooves in the disk being sensed by an infrared LED and sensor; the magnetic head touches the recording surface. The optical servo tracks allow for an increase in the tracking precision of the magnetic head, from the usual 135 tracks per inch to 1250 tracks per inch.
Floptical disks provide 21 MB of storage. The drive has a second set of read/write heads so that it can read from and write to standard 720 kB and 1.44 MB disks as well. To allow for a high degree of compatibility with existing SCSI host adapters, Floptical drives were designed to work as a standard floppy disk drive, not as a removable hard disk. To ensure this, a "write lockout" feature was added in the firmware; this inhibits writing of the media. It is possible to unlock the drive by issuing a SCSI Mode Sense Command, 1A 00 20 02 A0, it is unclear how much of a problem this is, Insite issued EPROMs where this "feature" was not present. At least two models were produced, one with a manual lever that mechanically ejected the disc from the drive, another with a small pinhole into which a paperclip can be inserted, in case the device rejected or ignored SCSI eject commands. Insite licensed the floptical technology to a number of companies, including Matsushita, Maxell/Hitachi and others. A number of these companies formed the Floptical Technology Association, or FTA, to try to have the format adopted as a replacement of standard floppy disks.
Around 70000 Insite flopticals are believed to have been sold worldwide in the product's lifetime. Silicon Graphics used them in their SGI SGI Indy series of computer workstations, it was reported that Commodore International had selected the Insite Floptical for its Amiga 3000. However, this did not take place, while Flopticals were installed in many Amiga systems, they were sold by either Insite, TTR Development or Digital Micronics, not bundled by Commodore. Iomega licensed the floptical technology as early as 1989 and produced a compatible drive known as the Insider. A few years a number of other companies introduced floptical-like but incompatible systems: Iomega introduced their own ZIP-100 system storing 100 MB in 1994, which would go on to sell into the tens of millions. Versions would increase the capacity to 250 and 750 MB. Another similar system was Imation's LS‑120 SuperDisk in 1996; the LS-120 stored 120 MB of data while retaining the ability to work with normal 3 1⁄2-inch disks, interfacing as a standard floppy for better compatibility.
A LS-240 version would store up to 240 MB. A smaller competitor was the unknown Caleb UHD144 in 1997. Since 1998 Sony tried their own floptical-based format, the Sony HiFD, but quality control problems ruined its reputation; the first version could store 150 MB. There was serious consideration that one of these systems would succeed where the Floptical failed and replace the standard floppy disk outright, but the rapid introduction of writable CD-ROM systems in the early 2000s made the market disappear. Support of Floptical drives is present in all Microsoft Windows NT operating systems up to Windows 2000, where it figures as 20.8 MB drive format option in the FORMAT command options. The FORMAT command in Windows XP and newer lacks support of the Floptical drive. Floptical support exists in SCO OpenServer as well. SCSI-equipped Macintosh computers could boot from a Mac operating system installed on a floptical. Silicon Graphics's IRIX operating system includes floptical support. Magneto-optical drive SuperDisk Zip drive Fred Charles.
"Manufacture of 21 MB Floptical disk using acousto-optically controlled laser ablation process". Proceedings SPIE 2062, Lasers as Tools for Manufacturing. Doi:10.1117/12.167584. LaPlante, Alice. "486 Group To Discuss High-Density Drives". InfoWorld: 5. Retrieved 2017-06-19. Yesterday's Technology. "Floptical Disks". Retrieved 2017-05-24. Curtis, Jason. Museum Of Obsolete Media, ed. "Floptical". Retrieved 2017-05-24. "Floptical Technology Primer". Iomega Corporation Publication. 1992. Retrieved 2017-10-01