Pinnacle Systems, Inc. TARGA 3000 Cookbook

TARGA 3000 Configuration Cookbook
11/25/2002 8
3 System Considerations
3.1 Which PCI Chipset is Best?
The i840 is the recommended chipset for high performance TARGA 3000 systems since it offers full support
for 64 bit PCI. In addition the ServerWorks chipsets have been certified, although they have the
disadvantage that only PCI graphics cards can be used with this chipset. There are problems performing
DMA transfers to AGP with the ServerWorks chipset, and so overlay cannot work in such configurations. In
addition the Intel 440BX, 850, 845 and i815 chipsets have been certified. These do not offer the same
performance as the 64 bit i840 (no more than 2 streams of uncompressed can be played), but are much
better value. More recently we have also certified the AMD-760MP chipset for use with the Athlon
processors. It is wise to follow the instructions in this cookbook to ensure that you will get the best
performance and compatibility out of your system.
3.2 What BIOS Will Work?
No known issues exist with the major BIOS vendors (American Megatrends or AMI), Phoenix, or Award at
this time. The BIOS is responsible for configuring the resources used by components in a system. After a
system boots, BIOS hands over a list of detected devices and I/O addresses to the Windows NT HAL
(Hardware Abstraction Layer). From here, Windows NT manages the allocation of system resources to all
supported devices. BIOSes are revised routinely by motherboard manufacturers, and can affect a system
configuration.
3.3 TARGA 3000, IRQs & DMA
The TARGA 3000 uses DMA (Direct Memory Access) channels to quickly transfer large amounts of data to
system memory and back, not IRQ (Interrupt Request). DMA transfers are more efficient than IRQ channel
requests, as they are not "interrupted" by time-share requests used by IRQ cycles. When a device requires
service from the processor, it flags the system by asserting a hardware interrupt request (IRQ) . Interrupt
requests have higher priority than normal operating code, so the processor has to stop what it was executing
and service the request before resuming.
That said, IRQ allocation at the BIOS level must still be managed. (Pinnacle's certification reports for both
systems and motherboards will show the preferred PCI slot and associated IRQ positions for typical TARGA
installations.) For instance, if two devices (such as network adapters or SCSI controllers and TARGA) are
assigned the same IRQ at the BIOS level, BIOS will happily report to NT's HAL that both devices can share
the same IRQ space. HAL may then continue the shared relationship, and performance may degrade for
one or both devices when both are used at peak levels. A quick check in NT's Diagnostics Resources applet
is a good place to start.
All interrupts have a priority:
(Highest Priority) NMI, IRQ 0, 1, 2, 9, 10, 11, 12, 13, 14, 15, 3, 4, 5, 6, 7, 8 (Lowest Priority)
Most of the interrupts are pre-assigned, leaving only three or four available for TARGA, SCSI controller(s),
sound cards and network adapters. BIOS usually shows IRQ 9, 10, and 11 available and possibly IRQ 5 and
15 to assign to any additional device. This is how IRQs are typically assigned:
NMI - Non-maskable interrupt used to signal serious failures.
IRQ 0 - System Timer IRQ 08 - Real-time Clock
IRQ 1 - Keyboard IRQ 09 - Available
IRQ 2 - Cascade Interrupt IRQ 10 - Available

Pinnacle Systems, Inc. TARGA 3000 Specifications

General

Brand	Pinnacle Systems, Inc.
Model	TARGA 3000
Category	Computer Hardware
Language	English