Other then being in between the main board and a peripheral device, how does a Controller work? Are they a buffer, change analog to digital etcetera?

Thank you for your expertise!

Theoretically and usually, what that controller card is designed to do.

What' the difference between the input to the card and the output?

If we go back a few years to the early PC days and pick a serial port card. A PCI card typically has an address/IRQ. Very simply the operating system/program via the serial driver sends data to the serial port's card address (default ttys0 3F8/IRQ4 ). The card reads the data off the bus and converts it to RS-232 signal levels which then appears on the 9 or 25 pin connector.

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Thank you for the info. Could you please direct me to what is the 'standard' that a Bus can accept? Is it just what defines digital data and speed like about .03V for zero and .42 for one?

It depends on the bus design and its architecture.

Is this for general knowledge or something more specific?

This might help.
https://en.wikipedia.org/wiki/PCI_Express

@Moderators: Isn't this guy trolling?


@theKbStockpiler: stop asking general questions. If you have a specific problem or question, outline it, along with the equipment you're having the problem on. If you want general information, do general reading.

I will give theKbStockpiler the benefit of the doubt...

I'm studying the main board of a IBM 5150. I think it' my best bet to see the interaction of software and hardware with out a million layers in between. I found a decent amount of literature on line to study how DOS interacts with the 5010 to use as a base to reference to a Linux From Scratch build.

A more direct question would be "what environment does the bus of a 5150 operate in"? I would actually assume that if the hardware did not output and receive just 1's and 0's the hardware was incomplete.

I did a search on 'card controllers' and you can't do much with the definitions given. I found some info on keyboard controllers which do actually describe how they transduce the motion of the key to data put on the bus.

Did you read this?
https://en.wikipedia.org/wiki/Indust...d_Architecture

The only thing built into the motherboard was the keyboard controller at the time. The 5150 only had floppies so the serial,parallel and video cards all plugged into the bus.

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Thank you for the link!That link led to this one.
http://www.interfacebus.com/Design_PCAT_Card.html

Controller card is a very general term. When you buy a computer it does not come with every possible communication interface supplied so you generally have specific cards connected to the computer by a PCI bus or similar. I'm old enough to remember other propitiatory connections like Sun Microsystem's S-bus, DEC's Unibus, SCSI buses, etc.

The computer only needs to have the ability to communicate to this level as the controller card handles the communication between the connected device(s) and the computer.

A RAID controller is used to configure and control RAIDed disks; initialise the RAID volumes, handle disk failures and rebuild volumes. Plus handle the data flow between the RAID virtual disks. All without CPU intervention.

Fibre HBAs handle communications between the computer bus and the LED or laser diodes which link to disk arrays, tape or other storage devices and networks.

Nics do the same between the computer and hubs, switches, routers, etc.

Comms protocols between the various devices tend to follow standards so controller cards are used to, er... control this data irrespective of what computer or OS is being used.

My

Play Bonny!

The IBM 5150 was an overrated POS in hardware terms foisted on a non savvy public. It aimed to be the computer of the future, but the design was so myopic, it's a wonder it survived. In it's defence, the hardware at the time was pathetic.

It's designed-in errors took the computer industry over 20 years to rid itself of. IMO, you can't learn much from a 5150 to base lfs on. LFS is software; you're studying Computer Hardware Archaeology. Most of the interface is handled by glibc libs. Once you've built glibc, you're done with hardware until the graphics. The 5150 uses an 8088 - a 16 bit cpu with an 8 bit data bus, (giving 16 bits in 2 chunks of 8). It has an ISA bus for controller cards. The buses have gone ISA --> EISA -->VLB --> PCI --> AGP --> PCIE, and the buses are used less and less as things are integrated. The 5150 had 182K of ram, whereas some boxes today have 64G!

That's still an ISA bus, which actually isn't - in THAT form - used anymore (it only had an 8-bits dataline, because the 8088 couldn't handle more then that anyway).
It got extended for the 80286 (PC/AT) and even the 80386.
Nowadays the PCI bus is the more standard one, although the faster PCI-X (eXpress) one is taking over.

AND expensive, it was geared to business, home users couldn't afford it.
.

BTW: the maximum memory of a 808x (86 OR 88) is 1 MB, of which in the design of IBM only 640 KB could be filled by RAM. Rest was reserved for I/O boards (and BIOS).