Zip drive

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This article is about the drive that reads and writes Zip floppy disks. For the ZIP archive file format, see Zip (file format).
Iomega ZIP-100 drive logo
External ZIP-100 drive (available in parallel port and SCSI versions)
An internal Zip drive installed in a computer
An internal Zip drive outside of a computer
The Zip disk media
Back of the ZIP-100 with parallel port printer pass-through

The Zip drive is a medium-to-high-capacity (at the time of its release) removable floppy disk storage system that was introduced by Iomega in late 1994. Originally, Zip disks launched with capacities of 100 MB, but later versions increased this to first 250 MB and then 750 MB.

The format became the most popular of the superfloppy products which filled a niche in the late 1990s portable storage market. However, it was never popular enough to replace the 3.5-inch floppy disk. Later versions of the disc matched the capacity available on rewritable CDs but this was far surpassed by the later rewritable DVDs. USB flash drives ultimately 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 later covered internal and external CD writers known as Zip-650 or Zip-CD, which had no relation to the Zip drive.


The Zip drive is similar to Iomega's earlier Bernoulli Box in that in both drives, a set of read/write heads mounted on a linear actuator hover over a rapidly spinning flexible medium mounted in a sturdy cartridge. However, the Zip cartridge lacks the Bernoulli plate of the earlier product,[1] and as a consequence, the Zip cartridge has only one disk in the cartridge in contrast to the two disks in a Bernoulli cartridge (one on either side of the Bernoulli plate). In the Zip drive, the heads fly in a manner similar to a hard disk drive, without the use of the Bernoulli effect. The linear actuator uses the voice coil actuation technology related to modern hard disk drives. The Zip disk uses smaller media (about the size of a 9 cm (3.5") microfloppy, but more ruggedised, rather than the Compact Disc-sized Bernoulli media), and a simplified drive design that reduced its overall cost.

This resulted in a superfloppy disk that had all of the 3.5" floppy's convenience, but held much more data, with performance that was much improved over a standard floppy drive (though not directly competitive with hard disk drives). However, Zip disk housings were much thicker than those of floppy disks.[2] The original Zip drive had a maximum data transfer rate of about 1 megabyte/second (comparable to 6× CD-R; although some connection methods were slower, down to approximately 50 kB/second for maximum-compatibility parallel "nibble" mode) and a seek time of 28 milliseconds on average, compared to a standard 1.44 MB floppy's typical 500 kbit/s (62.5 kB/s) transfer rate and several-hundred-millisecond average seek time. Typical desktop hard disk drives from mid-to-late 1990s revolved at 5400 rpm and had transfer rates from 3 MB/s to 10 MB/s or more, and average seek times from 20 ms to 14 ms or less.

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 3.5" 1.44 MB diskettes, but they had a lower data-transfer rate due to lower rotational speed.[3] The rivalry was over before the dawn of the USB era.


Later (USB, left) and earlier (parallel, right) Zip drives (media in foreground).

Zip drives are available in multiple interfaces including:

  • IDE True ATA (very early ATA internal Zip drives mostly sold to OEMs; these drives exhibit software compatibility issues because they do not support the ATAPI command set)
  • ATAPI (all Zip generations)
  • USB 1.1 (Zip 100 MB and 250 MB generations)
  • USB 2.0 (Zip 750 MB generation; backwards compatible with USB 1.1 systems)
  • IEEE 1284 (Parallel Port) with Printer passthrough (Zip 100 MB and 250 MB generations) (See NB 1)
  • IEEE 1394 (Firewire) (Zip 250 MB and 750 MB generations)
  • SCSI (Zip 100 MB and 250 MB generations; both internal and external editions; external editions limited to ID 5 and 6)
  • "Plus" (Zip 100 MB external drive with both SCSI and IEEE 1284 connections; SCSI ID limited to ID 5 and 6).

Parallel port external Zip drives are actually 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 used an AIC 7110 SCSI controller and later parallel drives (Zip Plus and Zip 250) used what was known as Iomega MatchMaker.[4][5] The drives are identified by the operating system as "IMG VP0" and "IMG VP1" respectively.

Early external SCSI-based Zip drives often came with an included SCSI adapter known as Zip Zoom. The Zip Zoom is a rebadged ISA Adaptec SCSI host controller. Also, originally sold separately was a PCMCIA-to-SCSI adapter for laptop compatibility, also a rebadged Adaptec.

Interface availability:

Name Interface
ATAPI SCSI LPT[note 1] USB FireWire[note 2]
Zip 100 Yes Yes Yes Yes No
Zip 250 Yes Yes Yes Yes Yes
Zip 750 Yes No No Yes Yes
  1. ^ Also known as IEEE 1284, Parallel Port
  2. ^ Also known as IEEE 1394 interface

Driver support:

NB 1: Requires a driver older than 5.x.[6]


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 slowly to 100 MB disks than the 100 MB drive, and the Iomega software is unable to perform a "long" (thorough) format on a 100 MB disk. (They can be formatted in Windows as normal; the advantage of the Iomega software is that the long format can format the 100MB disks with a slightly higher capacity. 250 MB disks format to the same size either way.) The 750 MB drive cannot write to 100 MB disks but can read existing disks.

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.

Sales, problems, and licensing[edit]

Zip drives initially sold well after their introduction in 1994, owing to their low price and high (for the time) capacity. The drive was initially sold for just under US$200 with one cartridge included, and additional 100 MB cartridges for US$20. At this time hard disks typically had a capacity of 500 MB and cost around US$200, and so backing up with Zip disks was very economical for home users—some computer suppliers such as Dell and Apple Inc. (before Steve Jobs' 1998 return to the company and his efforts to remove all floppy disk drives on the Macintosh platform) included Iomega internal Zip drives with their machines. Zip drives also made significant inroads in the graphic arts market, as a cheaper alternative to the Syquest cartridge hard disk system. 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, Toshiba and Maxell. Epson and NEC. NEC also produced a licensed 100 MB drive model with its brand name.

Zip Disk and Drive sales, 1998 to 2003

Sales of Zip drives and disks declined steadily from 1999 to 2003.[7] Zip disks had a relatively high cost per megabyte compared to the falling costs of then-new CD-R and CD-RW discs.

The growth of hard disk 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, followed by USB flash drives, pushed the Zip drive out of the mainstream market. Nevertheless, during their prime, Zip disks greatly eased the exchange of files that were too big to fit into a standard 3.5" floppy or an email attachment, and there was no high-speed connection to transfer the file to the recipient. 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 used to compete primarily with USB external hard drives and the Hi-MD version of Sony's MiniDisc, which stores up to 1 GB on a disk that is smaller and less expensive than a 100 MB Zip disk.

In September 1998, a class action suit was filed against Iomega over a type of Zip drive failure dubbed the "Click of Death", accusing Iomega of violation of the Delaware Consumer Fraud Act.[8]

In 2006, PC World rated the Zip drive as the 15th worst technology product of all time.[9] Nonetheless, in 2007, PC World rated the Zip drive as the 23rd best technology product of all time[10] despite its known problems.


Zip drives are still used today by retro-computing enthusiasts as a means to transfer large amounts (compared to the retro hardware) of data between modern and older computer systems. The Commodore-Amiga, Atari ST, Apple II, and "old world" Macintosh communities often use drives with the SCSI interface prevalent on those platforms. They have also found a small niche in the music production community, as SCSI-compatible Zip drives can be used with vintage samplers and keyboards of the '90s.

Zip disks are still in use (though fading) in aviation circles. For example, Zip disks are used by Jeppesen (a Boeing Company) for navigation database updates. Also, for example, avionics companies such as Universal Avionics supply TAWS, UniLink and Performance databases, which remain available via Zip Disk, for uploading into an FMS (Flight Management System) via SSDTU (Solid State Data Transfer Unit). "Updates are available for download from Universal Avionics web site or are provided on 3.5 inch disks, 100MB Zip Disks (SCN 603-604 and 703-704) or 512MB USB Flash drives."[11][12] [13]


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 used 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.[14]

The ZipCD 650 was able to record onto 700 MB CDs but could only burn data up to 650 MB. There was third-party firmware that forced the ZipCD 650 to be able to write data CDs up to 700 MB but made the drive unstable.

See also[edit]


External links[edit]

  • Media related to Zip disk at Wikimedia Commons