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(Redirected from PC card)
In computing, 'PC Card' (originally 'PCMCIA') is the form factor of a peripheral interface designed for laptop computers. It was originally for memory expansion, but the existence of a usable general standard for notebook peripherals led to all manner of devices being made available in this form. Typical devices include network cards, modems, and hard disks. The original use, for memory-expansion cards, is no longer common.
Many notebooks in the 1990s came with two type-II slots with no barrier in between (allowing installation of two type-II cards or one type-III card). With the removal of legacy ports, most contemporary notebooks only feature a single type-II card slot.
The United States computer industry created the Personal Computer Memory Card International Association to challenge the Japanese JEIDA memory card devices by offering a competing standard for memory-expansion cards. The two standards later merged as 'JEIDA 4.1' or 'PCMCIA 2.0' (PC Card) in 1991.
'PCMCIA' stands for ''Personal Computer Memory Card International Association''. While this acronym did clearly describe the original intentions of the organization's standard, it was difficult to say and remember and was sometimes jokingly referred to as "People Can't Memorize Computer Industry Acronyms" . To aid in the widespread marketing and branding of the standard and to account for the standards widening scope (beyond just memory cards) the association acquired the rights to simpler term "PC Card" from IBM and began using it (rather than "PCMCIA") from version 2 of the specification onward.
All PC Card devices use an identical 68 pin dual row connecting interface. All are 85.6 mm long and 54.0 mm wide. The form factor is also used by the Common Interface form of Conditional Access Modules for DVB broadcasts.
The original standard was defined for both 5 volt and 3.3 volt cards. The 3.3 V cards have a key on the side to protect them from being damaged by being put into a 5 V-only slot. Some cards and some slots operate at both voltages as needed. The original standard was built around an 'enhanced' 16-bit ISA bus platform.
Cards designed to the original specification (version 1.x) are type I and feature a 16-bit interface. They are 3.3 millimeters thick. Type-I PC Card devices are typically used for memory devices such as RAM, flash memory, OTP, and SRAM cards.
Type-II PC Card devices feature a 16- or 32-bit interface. They are 5.0 millimeters thick. Type-II cards introduced I/O support, allowing devices to attach an array of peripherals or to provide connectors/slots to interfaces for which the PC/laptop had no built-in support. For example, many modem, network and TV cards use this form factor. Due to their thinness, most type II interface cards feature miniature interface connectors on the card which are used together with a dongle; a short cable that adapts from the card's miniature connector to an external full-size connector.
Type-III PC Card devices are 16- or 32-bit. These cards are 10.5 millimeters thick, allowing them to accommodate devices with components that would not fit type I or type II height. Examples are hard disk drive cards, and interface cards with full-size connectors that do not require dongles (as is commonly required with type II interface cards).
Type-IV cards, introduced by Toshiba, have not been officially standardized or sanctioned by the PCMCIA. These cards are 16 millimeters thick.
CardBus are PCMCIA 5.0 or later (JEIDA 4.2 or later) 32-bit PCMCIA devices, introduced in 1995 and present in laptops from late 1997 onward. CardBus is effectively a 32-bit, 33 MHz PCI bus in the PC Card form factor. CardBus includes bus mastering, which allows a controller on the bus to talk to other devices or memory without going through the CPU. Many chipsets are available for both PCI and CardBus, such as those that support Wi-Fi.
The notch on the left hand front of the device is slightly shallower on a CardBus device, so a 32-bit device cannot be plugged into a slot that can only accept 16-bit devices. Most new slots are compatible with both CardBus and the original 16-bit PC Card devices.
The speed of CardBus interfaces in 32 bit burst mode depends on the transfer type; in byte mode it is 33 MB/s, in Word mode it is 66 MB/s, and in DWord mode it is 132 MB/s.
CardBay is a variant added to the PCMCIA specification in 2001. This was intended to add some forward compatibility with USB and IEEE 1394, but was not universally adopted and only some notebooks support CardBay features in their PC Card controllers.
The interface has spawned a generation of flash memory cards that set out to improve on the size and features of Type I cards: CompactFlash, MiniCard and SmartMedia. For example, the PC Card electrical specification is also used for CompactFlash, so a PC Card CompactFlash adapter need only be a socket adapter.
ExpressCard is a later specification from the PCMCIA, intended as a replacement for PC Card, built around the PCI Express standard. PC Card Standard is closed to further development and PCMCIA strongly encourages future product designs to utilize the ExpressCard interface. As of 2007, the majority of laptops now ship with only ExpressCard slots or neither slot type (leaving expansion to USB and Firewire only), though the Lenovo Thinkpad T60, among other models, currently ships with both CardBus and ExpressCard slots.
There is no general backward or forward compatibility between ExpressCard and CardBus sockets. CardBus devices do not fit ExpressCard sockets and ExpressCard devices do not fit CardBus sockets. Because of the differences in the interfaces, there are no general purpose adapters possible between the two formats. Some ExpressCard devices that use only USB technology can also operate with plain CardBus sockets with an adequate adapter. Also there are adapters that can accept PCMCIA cards and operate these in ExpressCard sockets. See Dual System Adapters for more.
The ''Card Information Structure'' (CIS) is information stored on a PC card that contains information about the formatting and organisation of the data on the card.[1]
The CIS also contains information about:
★ The type of card
★ Supported power supply options
★ Supported power saving features
★ The manufacturer
★ Model number
★ and so on.
When a card is unrecognised it is frequently because the CIS information is either lost or damaged.
1. Linux PCMCIA Programmer's Guide
★ USB for mobile modems
★ Zoomed video port
★ ExpressCard
★ PCMCIA official site
★
★ PC Card overview
★
★ PC Card FAQ
★
★ PC Card standard
★
★ CardBus white paper
★ Linux PCMCIA Information Page (kernel 2.4 and earlier)
★ Linux Kernel 2.6 PCMCIA
★ PCMCIA/CardBus Linux Status Survey
★ PCMCIA pinout
★ PCMCIA (PC Card) pinout and signals
★ Simple FAQ on PCMCIA & PC Card
In computing, 'PC Card' (originally 'PCMCIA') is the form factor of a peripheral interface designed for laptop computers. It was originally for memory expansion, but the existence of a usable general standard for notebook peripherals led to all manner of devices being made available in this form. Typical devices include network cards, modems, and hard disks. The original use, for memory-expansion cards, is no longer common.
Many notebooks in the 1990s came with two type-II slots with no barrier in between (allowing installation of two type-II cards or one type-III card). With the removal of legacy ports, most contemporary notebooks only feature a single type-II card slot.
The United States computer industry created the Personal Computer Memory Card International Association to challenge the Japanese JEIDA memory card devices by offering a competing standard for memory-expansion cards. The two standards later merged as 'JEIDA 4.1' or 'PCMCIA 2.0' (PC Card) in 1991.
| Contents |
| Name |
| Card types |
| Type I |
| Type II |
| Type III |
| Type IV |
| CardBus |
| CardBay |
| Descendants and variants |
| Card Information Structure |
| References |
| See also |
| External links |
Name
'PCMCIA' stands for ''Personal Computer Memory Card International Association''. While this acronym did clearly describe the original intentions of the organization's standard, it was difficult to say and remember and was sometimes jokingly referred to as "People Can't Memorize Computer Industry Acronyms" . To aid in the widespread marketing and branding of the standard and to account for the standards widening scope (beyond just memory cards) the association acquired the rights to simpler term "PC Card" from IBM and began using it (rather than "PCMCIA") from version 2 of the specification onward.
Card types
All PC Card devices use an identical 68 pin dual row connecting interface. All are 85.6 mm long and 54.0 mm wide. The form factor is also used by the Common Interface form of Conditional Access Modules for DVB broadcasts.
The original standard was defined for both 5 volt and 3.3 volt cards. The 3.3 V cards have a key on the side to protect them from being damaged by being put into a 5 V-only slot. Some cards and some slots operate at both voltages as needed. The original standard was built around an 'enhanced' 16-bit ISA bus platform.
Type I
Cards designed to the original specification (version 1.x) are type I and feature a 16-bit interface. They are 3.3 millimeters thick. Type-I PC Card devices are typically used for memory devices such as RAM, flash memory, OTP, and SRAM cards.
Type II
Type-II PC Card devices feature a 16- or 32-bit interface. They are 5.0 millimeters thick. Type-II cards introduced I/O support, allowing devices to attach an array of peripherals or to provide connectors/slots to interfaces for which the PC/laptop had no built-in support. For example, many modem, network and TV cards use this form factor. Due to their thinness, most type II interface cards feature miniature interface connectors on the card which are used together with a dongle; a short cable that adapts from the card's miniature connector to an external full-size connector.
Type III
Type-III PC Card devices are 16- or 32-bit. These cards are 10.5 millimeters thick, allowing them to accommodate devices with components that would not fit type I or type II height. Examples are hard disk drive cards, and interface cards with full-size connectors that do not require dongles (as is commonly required with type II interface cards).
Type IV
Type-IV cards, introduced by Toshiba, have not been officially standardized or sanctioned by the PCMCIA. These cards are 16 millimeters thick.
CardBus
CardBus are PCMCIA 5.0 or later (JEIDA 4.2 or later) 32-bit PCMCIA devices, introduced in 1995 and present in laptops from late 1997 onward. CardBus is effectively a 32-bit, 33 MHz PCI bus in the PC Card form factor. CardBus includes bus mastering, which allows a controller on the bus to talk to other devices or memory without going through the CPU. Many chipsets are available for both PCI and CardBus, such as those that support Wi-Fi.
The notch on the left hand front of the device is slightly shallower on a CardBus device, so a 32-bit device cannot be plugged into a slot that can only accept 16-bit devices. Most new slots are compatible with both CardBus and the original 16-bit PC Card devices.
The speed of CardBus interfaces in 32 bit burst mode depends on the transfer type; in byte mode it is 33 MB/s, in Word mode it is 66 MB/s, and in DWord mode it is 132 MB/s.
CardBay
CardBay is a variant added to the PCMCIA specification in 2001. This was intended to add some forward compatibility with USB and IEEE 1394, but was not universally adopted and only some notebooks support CardBay features in their PC Card controllers.
Descendants and variants
The interface has spawned a generation of flash memory cards that set out to improve on the size and features of Type I cards: CompactFlash, MiniCard and SmartMedia. For example, the PC Card electrical specification is also used for CompactFlash, so a PC Card CompactFlash adapter need only be a socket adapter.
ExpressCard is a later specification from the PCMCIA, intended as a replacement for PC Card, built around the PCI Express standard. PC Card Standard is closed to further development and PCMCIA strongly encourages future product designs to utilize the ExpressCard interface. As of 2007, the majority of laptops now ship with only ExpressCard slots or neither slot type (leaving expansion to USB and Firewire only), though the Lenovo Thinkpad T60, among other models, currently ships with both CardBus and ExpressCard slots.
There is no general backward or forward compatibility between ExpressCard and CardBus sockets. CardBus devices do not fit ExpressCard sockets and ExpressCard devices do not fit CardBus sockets. Because of the differences in the interfaces, there are no general purpose adapters possible between the two formats. Some ExpressCard devices that use only USB technology can also operate with plain CardBus sockets with an adequate adapter. Also there are adapters that can accept PCMCIA cards and operate these in ExpressCard sockets. See Dual System Adapters for more.
Card Information Structure
The ''Card Information Structure'' (CIS) is information stored on a PC card that contains information about the formatting and organisation of the data on the card.[1]
The CIS also contains information about:
★ The type of card
★ Supported power supply options
★ Supported power saving features
★ The manufacturer
★ Model number
★ and so on.
When a card is unrecognised it is frequently because the CIS information is either lost or damaged.
References
1. Linux PCMCIA Programmer's Guide
See also
★ USB for mobile modems
★ Zoomed video port
★ ExpressCard
External links
★ PCMCIA official site
★
★ PC Card overview
★
★ PC Card FAQ
★
★ PC Card standard
★
★ CardBus white paper
★ Linux PCMCIA Information Page (kernel 2.4 and earlier)
★ Linux Kernel 2.6 PCMCIA
★ PCMCIA/CardBus Linux Status Survey
★ PCMCIA pinout
★ PCMCIA (PC Card) pinout and signals
★ Simple FAQ on PCMCIA & PC Card
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