Difference between revisions of "Power Macintosh 8500"
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* [[Power Macintosh 7500/8500 Developer Note]]
* [[Power Macintosh 7500/8500 Developer Note]]
Revision as of 00:28, 2 July 2020
Similar Macintosh models include the Power Macintosh 7200, Power Macintosh 7500 and Power Macintosh 9500. Requires system software version 7.5.2 or later (8500/120), 7.5.3 or later (8500/132 and 8500/150) with appropriate System Enabler, and 7.5.3 Revision 2 (8500/150 8x-CD and 8500/180).
Introduced in August 1995, The 8500 brought 604 power and the PCI architecture to the mid-range, also boasting impressive AV features. The 8500 included a 120 Mhz 604 processor and 24-bit composite and S-video input and output. The processor of the 8500 shipped on a removable daughtercard. The 8500 came in a mini-tower case, sold for $4000, and was "speed bumped" to 132 and 150 Mhz in April 1996. It was speed bumped again to a 180 Mhz 604e processor in August, and was replaced in early 1997 by the 8600.
This is a smaller version of the Power Macintosh 9500.
The Power Macintosh 8500 and Workgroup Server 8550 feature three PCI expansion slots, a removable 604 microprocessor card, and, in addition, the Power Macintosh 8500 features video in and out functionality standard.
The Power Macintosh 8500 and WS 8550 computers feature the PowerPC 604 RISC microprocessor. The PowerPC 604 microprocessor is installed via a card that plugs into the logic board, allowing for maximum flexibility with future upgrades. Features of this microprocessor include
- Full RISC processing architecture
- Parallel processing units: one load-store unit, two integer units, one complex integer unit, and one floating point unit
- Separate built-in caches for data and instructions, 16 KB each, four-way set associative
- Advanced branching techniques for improved throughput
The Power Macintosh 8500 and WS 8550 logic boards have eight DRAM DIMM slots, each with a 64-bit data bus. You can increase the DRAM to a total of 512 MB using 5-volt, 64-bit-wide, 168-pin fast-paged mode, 70 ns DIMMs.
Note: These computers do not have any main memory soldered to the logic board. At least one RAM DIMM must be present for the computers to operate. DRAM DIMMs can be installed individually; however, if you wish to take advantage of the computer’s interleaving capability, which provides maximum performance, you must install the DIMMs in matching pairs and in paired slots (A4 and B4, A3 and B3, and so on).
The 8500 offers three PCI expansion slots.
The Power Macintosh 8500 comes standard with an AV module that provides support for: composite video input and output, S-video input and output, audio input (left and right), and audio output (left and right).
The Power Macintosh 8500 and WS 8550 computers offer Fast SCSI support on the internal SCSI connector, which provides for significantly enhanced data throughput. The internal SCSI bus on these computers supports transfer rates up to 10 MB/sec.
The Power Macintosh 8500 features 256KB L2 cache. This was expanded to 512KB for the Workgroup Server model 8550.
The Power Macintosh 7500 and 8500 computers have three expansion slots using the industry standard PCI bus. The PCI bus is a nonsplit bus with 32-bit multiplexed address and data. The PCI expansion slots in these computers use a 33 MHz system clock. The Power Macintosh 7500 and 8500 computers accept standard PCI cards as defined by the PCI Local Bus Specification, Revision 2.0. The cards are required to use the 5 V signaling standard and to use the standard ISA fence described in the specification. Each computer provides a total of 50 W of power for its three expansion slots. Both 5 V and 3.3 V are supplied; the total power at both voltages must not exceed the 50 W maximum.
Applications for the Power Macintosh 8500 computer should be free of the POWER-only instructions that were included in the PowerPC 601. The instruction set of the PowerPC 601 microprocessor includes some of the same instructions found in the instruction set of the POWER processor, and some compilers used to generate native code for earlier Power Macintosh models generated some of those POWER-only instructions. However, the PowerPC 604 microprocessor used in the Power Macintosh 8500 computer does not support the POWER-only instructions. When you compile applications for Power Macintosh computers, you should turn off the option that allows the compiler to generate POWER-only instructions.
Big-Endian and Little-Endian Bus Addressing
The Power Macintosh 7500 and 8500 computers support both big-endian and little-endian conventions for addressing bytes in a word. Byte order for addressing on the processor bus is big-endian and byte order on the PCI bus is little-endian. The Bandit IC performs the appropriate byte swapping and address transformations to translate between the two addressing conventions.
Resetting the Logic Board
Resetting the logic board can resolve many system problems. Whenever you have a unit that fails to power up, you should follow this procedure before replacing any modules.
- Unplug the computer.
- Remove the logic board.
- Using a small flat-blade screwdriver, pry open the latch at the end of the battery holder and lift off the battery holder cover.
- Remove the battery from its holder.
- Verify the power supply cable is disconnected from the logic board and then press the Power On button.
- Wait at least 10 minutes before replacing the battery. Make sure the battery is installed in the correct +/- direction.
- Reassemble the computer and test the unit.
Note: This procedure resets the computer’s PRAM. Be sure to check the computer’s time/date and other system parameter settings afterwards.