1. System Resources
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2. System Resources
Used to communicate…  Hardware with Software or Software with Hardware
4 Types of System Resources
(Interrupt Request)
(Direct Memory Access)
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3. System Bus Components
Made up of 3 Components  Data bus, Address bus, and Control bus
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4. System Resources and the Bus
System resources require specific lines on the bus:
Data uses the data bus
Memory addresses and I/O addresses use the address bus
IRQs and DMA channels are controlled by the control bus
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5. Interrupt Request Number (IRQ)
Used by hardware to tell the CPU “I need attention”  Hardware Interrupt
IRQs have a designated line on the bus for each IRQ that is available.
Some IRQs are either pre-assigned or used by standard devices.
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6. Interrupt Controllers
The original IBM PC used the fanciest interrupt controller chip they could get at the time, the 8259.
Unfortunately, it only could handle eight (8) interrupts.
With the IBM AT, they chained them together, placing another 8259 onto the IRQ2 of the first 8259
This gave a total of 15 interrupts
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7. Second Interrupt Controller Chip
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8. IRQ Priority The lower the IRQ number the higher the priority
Because the second controller is wired to IRQ 2, the IRQ priority order is as follows: 1
8, 9, 10, 11, 12, 13, 14, 15 3 4 5 6 7
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9. An Expansion Slot with Bus Lines
Original 8 bit IBM PC ISA expansion slot
SD# = Data bus line.
SA# = Address bus line.
IRQ# = IRQ line.
DRQ# = DMA line.
CLK = System clock signal.
#DC = Power line.
Expanded (16 bit) ISA expansion slot of the IBM AT
(which is what you have now)
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10. Device Manager From the Control Panel/System, load the Device Manager
From the “View” menu select “Resources by type”
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11. IRQ Assignments
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12. Devices Without IRQs Some devices don’t require IRQs
Software that runs continuously has the CPU check the device for service.
Called polling.
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13. Memory Address and I/O ports
Since the CPU is built to access memory (RAM), connected system devices can:
“map” to memory in the computer
This is where what seems like RAM to the computer is actually locations in the device
They behave like memory (RAM) to the CPU
Use I/O ports
Not like networking ports
Accessed like memory locations, but with different instructions in the CPU
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14. Memory Address Assignments
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15. I/O Addresses
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16. IRQs and I/O Addresses
The table lists standard IRQs and I/O addresses for devices on a computer system.
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17. How the Keyboard Uses its IRQ and I/O Address
You press a key on the keyboard
The keyboard controller sends its assigned IRQ to the CPU, thus saying, “I need attention.”
The CPU sees the IRQ and turns its attention to servicing it
The CPU uses the IRQ to point to a row in the I/O address table assigned to that IRQ to transfer data to / from the device.
Using that address it will find the key stroke data.
From the memory address table, the CPU locates the addresses in which the instructions to service the keyboard are stored.
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18. DMA Channels
Direct Memory Accessing is where information is copied from one location to another (usually to or from main memory) without the use of the CPU
In the original PC and AT, the CPU simply wasn’t fast enough to even copy data from a floppy or hard drive into main memory
More than one transfer can be going on at any one time, each transfer takes place through a “channel” (which just prevents conflicts – it isn’t actually separate wires or anything)
Concept is still used widely today (why waste CPU cycles on something simple and boring like memory transfers?) Your PC, PS3, Xbox, etc.
In the PC, used mainly by older devices, like floppy drives, tape drives, etc.
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19. Updating Device Drivers
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20. Updating Device Drivers
As part of this driver update process, you can update drivers from a hardware installation disk, a downloaded installer or from Windows Update
Open the Device Manager from the Control Panel
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21. Updating Device Drivers
Locate the hardware device where you want to update the drivers
After finding the hardware you're updating drivers for, right click on the hardware's name or icon and choose “Properties.” In this Properties window, click the “Driver” tab
Click the “Update Driver” button to start the Update Driver software wizard
On the How do you want to search for driver software? window, click on “Browse my computer for driver software”
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22. Updating Device Drivers con’t….
Locate the hardware device where you want to update the drivers
In the next window labelled Browse for driver software on your computer, click on “Let me pick from a list of device drivers on my computer,” located at the bottom of the window
Click the “Have Disk...” button located under the text box
Click the “Browse...” button on the Install From Disk dialog box that appeared
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23. Updating Device Drivers, con’t….
Navigate to the folders where the drivers are located
Click any INF file that displays in the file list and click the “Open” button (INF files are the only file type accepted by the Device Manager)
Click the “OK” button back on the Install From Disk dialog box
Choose the newly added hardware in the text box and then click the “Next >” button
The Windows 7 Update Driver Software wizard will now use the instructions provided in the INF file to install the updated drivers for your hardware
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24. Updating Device Drivers, con’t…. Updating Device Drivers
Navigate to the folders where the drivers are located
Follow any additional instructions on screen to complete the driver update
Note:
You may be asked to reboot the computer after the driver installation is completed
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25. Rolling Back Device Drivers
If an updated driver fails, you may need to roll back the driver to the previous version
Right-click the problem device and open the “Properties” window, then select the “Drivers” tab
Click the “Roll Back Driver” button
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