Zip drive
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The Zip drive is a medium-capacity removable disk storage system, introduced by Iomega in late 1994. Originally it had a capacity of 100 MB, but later versions increased this to first 250 MB and then 750 MB.
The format became the most popular of the super-floppy type products but never reached the status of a quasi-standard to replace the 3.5-inch floppy disk. It has been superseded by flash drive systems as well as rewritable CDs and DVDs, and is fading in popularity. The Zip brand was also used for internal and external CD writers known as Zip-650 or Zip-CD.
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[edit] Overview
The Zip system is based loosely on Iomega's earlier Bernoulli Box system; in both systems, a set of read/write heads mounted on a linear actuator flies over a rapidly spinning floppy disk mounted in a sturdy cartridge. The Zip disk uses smaller media (about the size of a 9 cm (3½") microfloppy, rather than the Compact Disc-sized Bernoulli media), and a simplified drive design that reduced its overall cost.
This resulted in a disk that has all of the 9 cm (3½") floppy's convenience, but holds much more data, with performance that is much quicker than a standard floppy drive (though not directly competitive with hard drives). The original Zip drive had a data transfer rate of about 1 megabyte/second and a seek time of 28 milliseconds on average, compared to a standard 1.44 MB floppy's 500 kbit/s (62.5 kB/s) transfer rate and several-hundred millisecond average seek time. Today's average 7200 RPM desktop hard drives have average seek times of around 8.5–9 ms.
Early generation Zip drives were in direct competition with the SuperDisk or LS-120 drives, which held 20% more data and could also read standard 3½" 1.44 MB diskettes, but they had a lower data transfer rate due to lower rotational speed. The rivalry was over before the dawn of the USB era.
[edit] Interfaces
Zip drives have been made with a variety of interfaces to the computer. Internal drives have been made with ATA, and SCSI interfaces. External drives have been made with parallel port and SCSI and (some years later) USB interfaces. For a while, there was a drive called the Zip Plus which was supposed to be able to autodetect between parallel and SCSI, but there were lots of compatibility problems reported and the drive was later dropped. The Zip Plus drive included additional software and a smaller power adapter than the original Zip drives. Eventually, USB Zip drives came to be powered from their USB connections.
[edit] Capacity
The initial Zip system was introduced with a capacity of 100 megabytes. Plans were considered for a lower cost 25 MB version that would work in the same 100 MB drive — the idea being to bring the price of a Zip disk closer to that of an ordinary floppy — but these disks seem not to have been released. The introduction of the 100 megabyte disk quickly made Zip a success and people used them to store files larger than the 1.44 MB capacity of regular floppy disks. As time went on, Iomega eventually increased the capacity to 250 and later 750 megabytes, while improving the data transfer rate and seek times.
[edit] Media
Zip media are thicker and slightly wider than 3.5" (9 cm) floppy disks. The extra thickness allows space for centrifugal force to hold the rotating disk away from its protective shell at high speeds, eliminating friction heat that limited the RPM (and therefore transfer speeds) of previous generations of magnetic media diskettes. This non-contact approach also increases the theoretical life of the media.
The underside of Zip media cases include a retroreflective spot in one corner. The drive mechanism will not engage if the reflective spot is not detected. This was a measure to reduce counterfeit low cost media from undercutting Iomega's profits (as the reflective inserts were used under license). Note that higher capacity disks, 250MB and 750MB, do not have the same reflective spot as the 100MB disk.
Zip disks are traditionally packed in clear plastic, two-piece jewel cases similar to those used by smaller MiniDisc media. They are somewhat thinner than standard (three-piece) CD jewel cases, but still thicker than slimline CD cases.
[edit] Compatibility
Higher capacity Zip disks must be used in a drive with at least the same capacity ability. Generally, higher capacity drives also handle lower capacity media. However, the 250 MB drive writes much more slowly to 100 MB disks than does the 100 MB drive, and it's unable to perform a long (i.e., thorough) format on a 100 MB disk. The 750 MB drive cannot write to 100 MB disks at all, though they are the cheapest and most common of the three formats.
The retroreflective spot differs on the three media sizes such that if a larger disk is inserted in a smaller capacity drive, the disk is immediately ejected again without any attempt being made to access the disk.
[edit] Features and implementation
[edit] Write protection
Unlike other diskette formats, the Zip's write protection is implemented both in software and in hardware instead of just in the disk controller itself. The metadata on the disk indicates the write protection status, which the drive then enforces to the host computer. To change protection settings, the computer issues commands to the drive to change the metadata on the Zip disk. This means that the disk must be loaded in a drive and accessed on a computer with the appropriate software to turn write protection on or off. It also means that, in theory, a rogue driver or a modified Zip drive could be created which ignores the write protection flag.
[edit] Media access protection
The Zip system also introduced media access protection via a password. Like write protection, this is also implemented on the software level. When a disk is inserted, the Zip drive reads the metadata; if the data indicates the disk should be read-locked, the drive awaits a password from the computer. Until it receives such a password, the drive pretends to still be empty (to basic disk I/O commands). Once the password has been sent and verified, the drive "activates" the disk in the drive and allows access. One side effect of this implementation is that, on some drive models, it is possible to trick the software into allowing access to a different disk than it believes to be in the drive, thereby bypassing the password protection. The protection does not use any encryption; it simply is a combination of metadata on the disk and cooperation from the Zip drive's firmware.
[edit] Error protection
The Zip disk media had extra blocks called spare sectors, which the drive used for proactive data loss prevention. When the drive detected a potential media defect (such as having to retry a read a few times before it succeeded, or excessive use of the error correction bits), it would relocate the data to a spare sector on the disk. This was done before the sector became completely unusable (a bad sector). The disks had a mapping of address sectors to physical sectors, so that this would be nearly transparent to the operating system.
[edit] Sales, problems, and licensing
Zip drives initially sold well after their introduction in 1994, owing to their low price point and high (for the time) capacity. The drive was initially sold for just under $200 USD with one cartridge included, and additional 100 MB cartridges for $20. At this time hard disks typically had a capacity of 500 MB and cost around $200 USD, and so backing up with Zip disks was very economical for home users. The price of additional cartridges swiftly dropped further over the next few years, as more companies began supplying them. Eventually, the suppliers included Fujifilm, Verbatim, and Maxell. Epson also produced a licensed 100 MB drive model with its brand name.
Sales of Zip drives and disks declined steadily from 1999 to 2003.[1] In September 1998, a class action suit was brought against Iomega over a type of Zip disk failure dubbed the click of death. Zip disks also had a relatively high cost per megabyte compared to the falling costs of CD-R and DVD±RW.
The growth of hard drives to multi-gigabyte capacity made backing up with Zip disks less economical. Furthermore, the advent of inexpensive recordable CD and DVD drives for computers, as well as USB flash drives, pushed the Zip drive out of the mainstream market. However, the advantages of magnetic media over optical media and flash memory, in terms of long-term file storage stability and high erase/rewrite cycles, still affords them a niche in the data storage arena. In such applications, Zip competes primarily with USB external hard drives and the Hi-MD version of Sony's MiniDisk, which stores up to 1GB on a disk that is smaller and less expensive than a 100MB Zip disk.
In 2006, PC World rated the Zip drive as the 15th worst technology product of all time.[2] However, in 2007, PC World rated the Zip drive as the 23rd best technology product of all time.[3]
[edit] The ZipCD Drive
Iomega also produced a line of internal and external recordable CD drives under the Zip brand in the late 1990s, called the ZipCD 650. It used regular CD-R media and had no format relation to the magnetic Zip drive. The external models were installed in a Zip drive-style case, and utilised standard USB 1.1 connections.
Iomega used the DirectCD software from Adaptec to allow UDF drive-letter access to CD-R or CD-RW media.
The company also released their own CD-R and CD-RW media under the same ZipCD name. However, the ZipCD drives would burn to any blank CD-R or CD-RW media.
Early models of ZipCD drives were rebadged Philips drives, which were also so unreliable that a class action lawsuit succeeded.[4]
[edit] See also
[edit] References
- ^ Anuual reports from corporate website:
- Iomega Corporation (2000). 2000 Annual Report to ShareholdersPDF (2.74 MiB)
- Iomega Corporation (2001). 2001 Annual Report to ShareholdersPDF (439 KiB)
- Iomega Corporation (2002). 2002 Annual Report to ShareholdersPDF (875 KiB)
- Iomega Corporation (2003). 2003 Annual Report to ShareholdersPDF (764 KiB)
- Iomega Corporation (2000). 2000 Annual Report to ShareholdersPDF (2.74 MiB)
- ^ PC World: The 25 Worst Tech Products of All Time
- ^ PC World: The 50 Best Tech Products of All Time
- ^ Philips and Hewlett-Packard CD Recorder Class Action
