Interrupt ReQuest (IRQ) is an hardware interrupt on a PC. There are 16 IRQ lines used to signal the CPU that a peripheral event has started or terminated. Except for PCI devices, two devices cannot use the same line. If a new expansion card is preset to the IRQ used by an existing board, one of them must be changed. This was an enormous headache in earlier machines.
Starting with the Intel 286 CPU in 1982, two 8259A controller chips were cascaded together and bumped the IRQs from 8 to 16. However, IRQ 2 is lost because it is used to connect to the second chip. IRQ 9 may be available for general use as most VGA cards do not require an IRQ.
PCI to the Rescue
The PCI bus solved the limited IRQ problem, as it allowed IRQs to be shared. For example, if there were only one IRQ left after ISA devices were assigned their required IRQs, all PCI devices could share it.
An eye for eye ends up making the whole world blind. – Mahatma Gandhi
Knowledge is power – Francis Bacon
Hitch your wagon to a star. – Ralph Waldo Emasco
Glory is fleeting, but obscurity is forever. – Napoleon Bonaparte
People demand freedom of speech to make up for the freedom of thought which they avoid. – Soren Aabye Kierkegaard
Only a life lived for others is a life worthwhile. – Albert Einstein
Learn from the mistakes of others. You can’t live long enough to make them all yourself. – Eleanor Roosevelt
In this space, and in this time, I am an essential person to the world. My journey in life is unique. It is MY journey.
The smartphone has just gotten a little bit dumber.
Neon colored silicone skins, at times filled with glittery materials, are to be used for absorbing shock when dropping your smartphone, as a waterproof case, and a stylish statement. The waterproof case is still under testing. The jelly like material is to be used in a soft skin like case that covers all sides of your smartphone, and a very thin skin of transparent silicone is to cover the front and back of the case, sealing it, to make it water proof, or at least water resistant. The release timeframe is targeted for this summer, when people hope to enjoy…additional uses for silicone on the beaches.
Todays Scuttlebot: Smart Shoes and the Top Social Network Among Teens – NYTimes.com.
A random thought regarding this article and word association: A ‘pen’ can have two modes, and a built in Bluetooth transmitter for communication to and from your smartphone.
The initial mode of the thin ‘pen’ like device allows the person/student to read the question using Optical Character Recognition by moving the thin pen like device over the question. The question is wirelessly transmitted to your smartphone, then the second mode of the device receives the answer from the smartphone in your pocket using the smartphone search, and can allow the user to have a simple output of ink, by rolling the highlighter against a white background. The inverse of the highlighted area would contain the letters for the answer. A bonus is to have disappearing highlighting ink. Just an idea, kids.