Compact Flash (CF ) is an interface standard for digital storage media, among other things. It comes mainly in the form of CF cards in digital cameras, but also in network components, computers, and personal digital assistants (PDA ) are used.

  • 5.1 designs
  • 5.2 interface
  • 5.3 CFast


The CompactFlash memory cards are as opposed to hard drives or CD drives usually storage media with no moving parts. The information is stored in a rewritable flash memory permanently. However, IBM produced the meantime CF - II cards with small hard drives as storage medium. This product was known as the Microdrive and had the advantage of a better price -performance ratio. Later, there were other manufacturers disk -based CF cards. Because of the decline in prices of flash memory these solutions, however, are almost completely disappeared from the market between 2005 and 2006.

CompactFlash cards are flash memory have still managed a controller of the memory besides the actual memory chip and offers outside an (E ) IDE interface, however, differs from conventional IDE interfaces in the shape of the plug. In contrast to all other flash-based memory card is responsible for the addressing, the actual internal memory of the card controller, and not the terminal (such as the digital camera). The rather intricate details of the flash memory control therefore remain hidden from the host device. When there is support from the memory for a file system that can address more memory ( such as FAT32 over FAT16 ) CF card can be read with a high capacity even of old equipment.


With digital storage media ( for digital cameras) was the CompactFlash technology for a long time market leader, but is displaced since the late 2000s increasingly of the Secure Digital Card (SD). Depending on the manufacturer of digital SLR cameras are usually still used CompactFlash cards in the professional field, while it frequently SD cards are in the entry-level segment with the new models. The preference for CF cards in the professional field explained by the fact that these offer faster transfer rates and larger amounts of memory compared to SD cards. CompactFlash has mostly metal casing, which makes the cards more robust than SD. The contacts are housed securely and memory cards are compatible with IDE and PCMCIA, so they are quick and simple to use as a hard drive replacement with adapters. This advantage is insignificant in the entry area. Some manufacturers also offer the possibility of various types of memory cards (simultaneously) deploy (on selected models ).

Areas of application

The most common are CompactFlash cards probably encountered as a storage medium in digital cameras, here especially in the professional field as of press photography. The professional digital mobile audio recording virtually always works with CompactFlash, if from space, power or weather reasons no disk or disc systems are used.

Since they have no moving parts, CompactFlash cards are relatively insensitive to shocks and are therefore suitable for use in industrial and mobile systems. They are often used there as the only permanent memory. The computer industry some manufacturers can be optionally configured with a fixed integrated CompactFlash slot or IDE port. In this case, the CompactFlash card is usually re-partitioned and formatted with a different file system than the standard delivered. For Linux or QNX systems, the common practice is.


Other cards by CompactFlash

For the Compact Flash slot, there are adapters that allow different memory cards can be used. For example, MultiMediaCard, SDHC and microSDHC memory cards can be used in devices with CompactFlash slots. As for backward compatibility with smaller memory cards, CompactFlash has the greatest flexibility for future memory sizes, because only the controller of the adapter you are using and the size of the card used to limit the usable memory size. There are restrictions on older devices, since this partly support only FAT16 and thus limit the capacity of the memory card by software on 8/16GB.

Compact Flash IDE after

Since the CompactFlash card has an IDE interface, a passive adapter is sufficient (ie a piece of printed circuit board with lines connecting the contacts of the card with the corresponding pins of an IDE connector ) to use them instead of an IDE hard disk can ( see comparison). In desktop computers, the adapter also requires a plug for the power supply of the card which is missing from the IDE ribbon cable used there. Because the 44- pin version of the IDE interface of notebook provides a power supply to use in place of a hard disk and by means PC-Card/PCMCIA-Adapter without additional power supply is possible. In the 40-pin ZIF cable that connects to the hard drive or SSD in a few sub-notebooks, the power supply is also included.

Some cards give yourself as a removable disk ( removable ) to recognize what some operating systems and programs prompted to refuse installation on it. This identification, however, is changeable.



  • CF Type I ( 36.4 mm × 42.8 mm × 3.3 mm )
  • CF type II ( 36.4 mm × 42.8 mm × 5.0 mm), sometimes referred to as " Microdrive compatible " because all Microdrives are Type II cards.

The only difference is thus the thickness of the design. Therefore, work type - I cards in a Type II slot.


While the external shape remained unchanged, the CF standards were adapted to progressive capacities and bandwidths.

  • CompactFlash 1.0 (1994 /1995) 8.3 MB / s ( PIO mode 2 )
  • 128 GiB (137 GB) potential capacity, as with IDE
  • Compact Flash , also Compact Flash I / O ( 1997) Cards that do not have memory function, but, for example, enable radio reception.
  • CF and CompactFlash 2.0 ( 2003) 16.6 MB / s ( PIO mode 4 )
  • The end of 2003 the integration of highly accelerating DMA accesses it was decided; integrated in CF 2.0 cards from mid-2004.
  • CF and CompactFlash 3.0 (2004) 66 MB / s ( UDMA 66)
  • 25 MB / s in PC Card mode
  • Map by password protectable
  • CFA recommends FAT32 to cards with capacities of more than 2 GiB, without FAT32 prescribe
  • CF and CompactFlash 4.0 (2006) 133 MB / s ( UDMA 133)
  • Map by password protectable
  • CF and CompactFlash 4.1 (2007) Advanced power saving
  • Compact Flash 5.0 (2010) 48 - bit sector addressing via LBA -48 (mandatory). Thus, the previous limit of 128 GiB (137 GB) is repealed. Maps can theoretically to 128 PiB (144 PB ) summarize. In addition, acceleration by transferring up to 32 MiB large blocks instead of the current maximum of 128 KiB in large blocks.
  • Trim command (mandatory). Speeds up writes.
  • ATA command set ATA -6 & ATA-8/ACS-2 (optional). Adaptation to the progress of the ATA standards
  • Power control (optional). Guaranteed certain transmission rates (important for live streaming or video - recordings)
  • Transmission of the CF version number (mandatory). In this way, the CF device can adjust more easily to the capabilities of the card.
  • Altered electrical specifications (obligatory) to improve compatibility with the ATA standard.
  • CompactFlash 6.0 (18 November 2010) Ultra DMA Mode 7 for up to 167 MB / s
  • Sanitize clear command corresponding to INCITS T13 ACS -2.
  • Trim Usage Guidelines for better write performance.
  • Temperature profile (optional )

The above standards are upward and downward compatible.


With the CFast standard, the faster SATA protocol is employed. These cards are not compatible in the connections to the classical CompactFlash cards.

  • CompactFlash Serial ATA Transfer ( CFast ) 1.0 (2008) 300 MB / s (Serial ATA 3.0 Gb / s)
  • Hot Swap
  • Same case dimensions as before, but do not plug compatible with Compact Flash
  • Normal SATA data port, proprietary power connector
  • First products in late 2009
  • CompactFlash Serial ATA Transfer ( CFast ) 2.0 ( 2012) 600 MB / s Serial ATA ( 6.0 Gbit / s)
  • New housing dimensions, especially flat
  • First products planned in 2013

Data available CF cards

All cards can be operated with both voltages.

The details vary by manufacturer and product range, as can terms such as " Professional", "Ultra" and "Extreme" denote different qualities. When the leader SanDisk Ultra cards achieve a transfer rate of about 30MB / s ( read and write) and Extreme Pro models up to 100 MB / s ( read and write). The Lexar introduced in early 2012 before a model with up to 150 MB / s (read).

Depending on the manufacturer, the speed is specified either as the multiples on the reading speed of CD -ROM drives ( at Kingston or Transcend ) or declared ( SanDisk ) with the maximum data transfer rate. The base unit ("1 × " ) is historically based on the basic speed of the CD -ROM drives, which at one times the reading speed to achieve a transfer rate of 153.6 kb / s in the CD - ROM Mode 1, this value to 150 kB / s is rounded. The following table compares the usual speed designations and maximum data transfer rates.

Other CF devices

With CF I / O Compact Flash offers the possibility of not only memory to connect other devices. Because of the logical and mechanical similarity to the PC Card standard it is easy for producers to make appropriate card as a CompactFlash variant. The CompactFlash slots of PDAs are used to bind to 56K, GSM, and GPRS modem and Bluetooth, Ethernet and Wi-Fi adapter, GPS and radio receivers, digital cameras, USB host adapter, and even graphic cards. Such adapters are usually in full, so designed as CF Type II.