Detailed Multimedia PC Specification (76873)

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CPU

Intel 80386sx minimum

RAM

2 megabytes of extended (linear address space) memory

Magnetic Storage

3.5-inch high-density (1.44) floppy disk drive

30 MB hard disk drive minimum

Optical Storage

CD-ROM drive with:

Sustained 150K/second transfer rate
Average seek time of 1 second or less
10,000 hours MTBF
Mode 1 capability (mode 2 and form 1&2 optional)
Subchannel Q (subchannels P and R-W optional)
MSCDEX 2.2 driver that implements the extended audio APIs

The drive must be capable of maintaining a sustained transfer rate of 150K/second, without consuming more than 40 percent of the CPU bandwidth in the process. This requirement is for read block sizes no less than 16K and lead time of no more than is required to load the CD-ROM buffer with 1 read block of data. We recommend that the drive have on-board buffers of 64K and implement read-ahead buffering.

If R-W support is provided, additional APIs must be implemented in the MSCDEX driver. Specifications for these additional APIs are available from Microsoft.

Read-ahead buffering is described in a specification available from Microsoft.

Audio

CD-ROM drive with CD-DA (Red Book) outputs and a front panel volume control. As an option, CD-ROM XA may be provided.

8-bit (16-bit recommended) Digital-to-Analog Converter (DAC) with:

Linear PCM sampling
DMA or FIFO buffered transfer capability with interrupt on buffer empty
22.05 and 11.025 kHz sample rate mandatory
44.1 kHz sampling rate desirable
Optional stereo channels
No more than 10 percent of the CPU bandwidth required to output 11.025 or 22.05kHz: no more than 15 percent for 44.1kHz

8-bit (16-bit recommended) Analog-to-Digital Converter (ADC) with:

Linear PCM sampling
11.025 kHz mandatory, (22.01kHz, or 44.1kHz sampling rate optional)
DMA or FIFO buffered capability with interrupt on buffer full
Microphone input

Internal synthesizer hardware with multivoice, multitimbral capabilities, six simultaneous melody notes plus two simultaneous percussive notes.

Internal mixing capabilities to combine input from three (recommended four) sources and present the output as stereo, line-level audio signal at the back panel.

Video

VGA compatible display adapter, and a color VGA compatible monitor.

A basic Multimedia PC uses mode 12h (640 x 480, 16 colors). An enhanced configuration referred to as "VGA+" is recommended with 640 x 480, 256 colors. The recommended performance goal for VGA+ adapters is to be able to bit block transfer (bitblt) 1, 4, and 8 bit-par-pixel DOBs (device independent bitmaps) at 350K pixels/second given 100 percent of the CPU, and at 140K pixels/second given 40 percent of the CPU. This recommendation applies to run full-length encoded images and non-encoded images. The recommendation performance is needed to fully support high-performance applications such as synchronized audio-visual presentations.

User Input

Standard 101-key IBM-style keyboard with standard DIN connector.

Two button mouse with bus connector.

I/O

Standard 9-pin or 25-pin asynchronous serial port, programmable up to 9600 bits per second (BPS), switchable interrupt channel.

Standard 25-pin bidirectional parallel port with interrupt capability.

1 MIDI port with In, Out and Thru, must have interrupt support for input and FIFO transfer.

IBM-style analog or digital joystick port.