구차니의 잡동사니 모음

Legacy port status and USB

Today's laptops frequently do not include PS/2 ports and so the port is now regarded as a legacy port on Wintel, having been superseded by USB. Many current keyboards and mice support both USB and PS/2 with a simple wiring adapter and active adapters are available which plug into a USB port and provide a pair of PS/2 ports (active adapters in the other direction are very rare). PS/2 ports however, can still be found on modern desktop computer motherboards, although a few newer motherboards have no PS/2-port or only the keyboard port, but most still have them. These PS/2 ports cause fewer problems when KVM switching with non-Wintel systems.

In computing, a zoomed video port (often simply ZV port) is a unidirectional video bus allowing a device in a PC card slot to transfer video data directly into a VGA frame buffer, so as to allow laptops to display real-time video. The standard was created by the PCMCIA to allow devices such as TV tuners, video inputs and MPEG coprocessors to fit into a PC card form factor and provide a cheap solution for both the laptop manufacturer and consumer.

The ZV port is a direct connection between the PC card slot and VGA controller. Video data is transferred in real time without any buffering, removing the need for bus mastering or arbitration.

The ZV port was invented as an alternative to such methods as the VAFC (VESA Advanced Feature Connector).

A ZV-enhanced PCMCIA port accepts standard cards in addition to Motion Picture Experts Group (MPEG) cards that are ZV-compliant. A ZV-compliant MPEG card utilizes internal software to change the pin-out configuration of the port in order to provide a dedicated video bus. The card also features built-in ports for accepting video-in signals. By connecting devices to the video-in ports on the ZV-card, the ZV port becomes a capture port.

Using the ZV port with a MPEG ZV-compliant card, a laptop or notebook can capture television programs and record them to hard disk. The incoming signal is first displayed full-screen, then software hands off the signal to the CPU to process for storage on the hard disk. A ZV port card also captures digital audio and can play back in full digital surround sound. The MPEG ZV-card is the equivalent of an add-on desktop TV tuner card.

In addition to capturing programs, a ZV port card can also be used for streaming live video conferencing, gaming applications, and making home movies. Software provides the ability to edit movies for a professional-style home video studio.

Video input ports vary on MPEG ZV-compliant cards depending on the card itself. Most cards include composite video-in, S-Video and cable-in. Some utilize a single proprietary port that uses a multi-purpose cable or dongle which accommodates all of these tasks, even supporting a remote control. Typically, ZV port cards also feature composite and S-Video output for watching the movies you’ve created on an external monitor such as a television.

BogoMips (from "bogus" and MIPS) is an unscientific measurement of CPU speed made by the Linux kernel when it boots, to calibrate an internal busy-loop. An oft-quoted definition of the term is "the number of million times per second a processor can do absolutely nothing."

/* simple loop based delay: */

static void delay_loop(unsigned long loops)
{
  int d0;
  __asm__ __volatile__(
    "\tjmp 1f\n"
    ".align 16\n"
    "1:\tjmp 2f\n"
    ".align 16\n"
    "2:\tdecl %0\n\tjns 2b"
    :"=&a" (d0)
    :"0" (loops));
}