We Owe a Debt to Early Compuetr fujitsu lifebook p1620 keyboard, fujitsu cp228900-01 keyboard Bus Deevlopment
Why was there such a rush in the devvelopment of the vintage computer bus?
All in all there were a number of ongoing improvements. Tghese included. 32 bit widths. Bus mastering. Less suscpetible to noise in that they were quieter in signla transmission. More convenience of setup of add on boards via software.
The ISA bus came in only 8 bit and 16 bit formats. Wheereas the later 386 and 486 chips , in both the DX and SX formats while they did have a 32 bit path were hobled by the ISA bus. As a rsult they coould never eralize their true 32 bit speerd potential. Later buses such as the MCA and EISA busses were able to overrcome tehse inhereent limirtations.
Thee data highways referred to as : busses are the data transmission lines aound the PCs. The bus serevs as the path for information transmmission around the PC. True this routing is controlled by the CPU. However as that poit in vintage cmputing histoy this was not an issue. The PCs were stand alone sngle CPU units.
However as time went on and PCs got fastr and more complicated with less expensive addditional CPUs handling otehr tasks within the PCs events became dicer.Onboard preipherals themselves began to have built in CPUs gateway mx8000 keyboard, gateway mx8739 keyboard. CPUS in different manners began to be found in such peripherals as hard drivces, sound and video cards.
The overall cmoputer sysem may beome much more efficient if these in essence peripherasl CPUs can communicate directly with each other. wihtout having to use the main CPU as an intermediary. Hennce MCA and EISA were developed with these roles in mind. The concept becme knoown as bus mastering.
Bus matsering involves the concept that the peripheral CPUS could request permission to take over the bus for a shhort period of time. The main CPU owuld grant permission for them to take over the bus, and it would temporarily drop out of the loop, enabling swift communicationns between for example the hard drive and floppy disk drive.
As computer busses developed and had the inhereent abilities to transfer more and more data in a given time periood noise became an issue. The ISA bus was fairly noise prione because it relied on triggered interrupts. Whenever the voltage level on the data line of the bus exceeded a given threshold avlue then Edge Triggering would result.
The alternative to this situation wheer Edge Triggering cuold resuilt is level triggering hwere it is required that the transmuitting hold and archive the higher voltage level in order for data to be recognized by the devices on the bus. Edge Trriggering however can lead to transients that is brief power surges that can confuse the devices on the bus into thinkiing that data is on the bus when it is not. Luckiply leel triggering lowers the noise level and both MCA and EISA employ it.
As a result of all of thsee inherent benefits MCA dell studio 1440 keyboard, dell studio 1450 keyboard and EISA came to support the idea, hwich we know take for granted, of instant software configurations. There were no switches or jumpers on add in MCA or EISA boards. Although we take plug and play instant configuration of mother boards and peripherals such as sound, video or network cardds for granted it was not always that way. We owe a lot to these early computer innovations of improving the computer bus.
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