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Windows 95 > Fine Tuning Windows 95


Update your (Intel) Hard Disk Controller

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IMPORTANT: Know what you're doing when using this information! You might have to re-install your system when getting it wrong (So make a backup before)! I provide links to the documents at Intel® where you can read the full information. I provide this information because people are asking for it. It is YOUR system, it is YOUR responsibility!

There are 2 updates available from Intel, which allow you to take full advantage of your Hard Disk Controller.

NOTE: These utilities are designed for and tested with Windows 95* only.

Windows 95 INF Update Utility for Intel® Chipsets

This INF Update utility program updates several Windows 95 INF files so that the latest Intel chipset components are recognized or configured properly in the system.

  1. The system must contain a supported Intel processor and chip set configuration:

    Chip set:

    • Intel 430HX, 430VX, 430TX, 440FX, 440LX, 440EX, 440BX and 440GX chip sets


    Processor:

    • Intel Pentium®, Pentium® with MMX™ Technology, Pentium® Pro, Pentium® II, Celeron™ processor, and Pentium® II Xeon™ processor devices ONLY


  2. One of the following versions of Windows 95 must be installed on the system prior to running the utility program.

    • Windows 95 4.00.950 (Retail)
    • Windows 95 4.00.950b (OSR2 without USB Supplement)
    • Windows 95 4.00.950b (OSR2.1 with USB Supplement)
    • Windows 95 4.00.950c (OSR2.5 with or without USB Supplement)


  3. A mouse has to be connected to the system

  4. These utilities should only be used on desktop systems and should not be executed on notebook or porTABLE systems with or without dock.

  5. It is assumed that all devices in system are enabled. These utilities may not work properly if there are devices in the system which are disabled.

For more information read the read-me file.

Please read the License Agreement!

Download the Intel Windows* 95 and Windows* 98 INF Update Utility [625KB].

Information on how to install can be found in the read-me file.

Troubleshooting issues can be viewed at Intel's Web site.

Bus Master IDE General Overview

Traditionally IDE devices where programmed to transfer data in PIO (Programmed I/O) mode. In this mode data is transferred to and from IDE devices via CPU instructions. This requires a relatively large amount of dedicated CPU time, especially when transferring large amounts of data. A typical machine today will use 40% of the CPU doing hard drive transfers in PIO mode and use only 25% of the CPU doing hard drive transfers in DMA mode, on the same hardware.

DMA (Direct Memory Access) mode of operation allows the DMA channels to handle data transfer so that it's not required for the CPU to monitor the transfer, thus reducing CPU overhead. The transfer rate for a particular data transfer event will not noticeably increase.

Theoretically DMA mode 2 allows up to 22.2Mb/sec and UDMA (Ultra DMA) allows up 33.3 Mb/sec, whereas PIO mode 3 & 4 allow only up to 16.6 Mb/sec. (But in real-world operation actual data I/O rates are significantly less for all).
More information on DMA and UDMA can be found at PCGuide.

You can use this procedure to test your HDD for DMA support.

Now to measure and compare the speed of your hard drive while operating in different modes I would suggest you to download the shareware utility called HD Tach.

The measurements which are important here are Read burst speed, Read speed and CPU utilization. When operating in PIO mode the Read burst speed is more or less equal as the maximum Read speed data transfer rate, whereas the CPU Utilization is typically above 30%. In DMA modes the Read burst speed is typically 25 to 50% higher than the Read speed data transfer rate, and the CPU Utilization usually drops below 25%. In UDMA modes the Read burst speed is typically double the Read speed data transfer rate (although it can be significantly less), and the CPU Utilization is usually the same as for DMA mode (less then 25%).


Intel Bus Master Driver

Intel® 430 and 440 chipsets can reduce this CPU time, via Bus Master IDE (BM-IDE) logic contained within the PIIXn IDE controller function. The PIIXn IDE controller acts as a PCI bus master on behalf of IDE DMA slave devices, performing DMA (Direct Memory Access) transfers to and from devices. Additionally, Intel® chipsets incorporating the PIIX3, PIIX4, and PIIX4E devices can perform fast DMA transfers via the UltraDMA/33 hardware interface

The TABLE below maps Intel chipsets to PIIXn devices and notes each chipset's IDE hardware interface:


Chipset PIIXn Device IDE h/w interface
430FX PCIset 82371FB (PIIX) ATA/16
430VX PCIset 82371SB (PIIX3) ATA/16
430HX PCIset 82371SB (PIIX3) ATA/16
430TX PCIset 82371AB (PIIX4) UltraDMA/33
440FX PCIset 82371SB (PIIX3) ATA/16
440LX AGPset 82371AB/EB (PIIX4/4E) UltraDMA/33
440EX AGPset 82371EB (PIIX4E) UltraDMA/33
440BX AGPset 82371AB/EB (PIIX4/4E) UltraDMA/33
440GX AGPset 82371EB (PIIX4E) UltraDMA/33

To be able to use the BM-IDE driver, these conditions have to be met:

Hardware Requirements:

  1. BM-IDE-capable Intel chipset configuration

    • Chip set: Intel 430FX, 430HX, 430TX, 430VX and 440FX chip sets
    • Processor: Intel Pentium®, Pentium® with MMX™ Technology, Pentium® Pro, and Pentium® II devices ONLY.

  2. A mouse has to be connected to the system
  3. It is assumed that the BIOS properly initialized the 82371xB IDE interface for Bus Master IDE operation.
  4. There are no other non-82371xB IDE controllers (add-in IDE controller or sound card with IDE) enabled on the system.
  5. DMA-capable IDE device(s)

    • Most IDE hard disk drives and CD-ROM drives shipping today are DMA-capable, this is usually noted in HDD or CD-ROM manual as supporting DMA or UDMA

      You can use this procedure to test your HDD for DMA support

Software Requirements:

  1. Operating system with multitasking capability

    • Microsoft Windows 95, Windows 98, Windows NT 4.0

  2. BM-IDE device driver

    • Windows 98, Windows 95 OSR-2, and Windows NT 4.0 Service Pack 3 ship with a BM-IDE device driver
    • Intel provides BM-IDE driver for Windows 95

  3. System BIOS that is BM-IDE-aware

    • Required if using Microsoft BM-IDE device drivers
    • Not required if using Intel BM-IDE device driver (Windows 95)

Should You Download the Intel BM-IDE driver for Windows 95?

First identify which version of Windows you are using by opening Start > Settings > Control Panel > Systems. On the General tab, the version number should be listed.

Use this TABLE to match the version number with the version name:

Windows Version Common Name
4.00.950 Windows 95 Retail
4.00.950a Windows 95 OSR 1
4.00.950b Windows 95 OSR 2.0/2.1
4.00.950c Windows 95 OSR 2.5
4.10.1998 Windows 98 Retail

If you have trouble identifying your version of Windows, the best way to tell your version is to use Tweaking Toolbox for Windows, one of it's functions is to show your Windows version.

For more information & free download, check the Tweaking Toolbox for Windows pages.

Tweaking Toolbox for Windows - Windows version tab


If you have the Windows 95 retail or OSR-1 release, you should download and install the Intel BM-IDE driver for Windows 95.

If you have the Windows 95 OSR 2, OSR 2.1, or OSR 2.5 releases, or Windows 98, you should not download the Intel BM-IDE driver, as these operating system versions already contain a BM-IDE driver from Microsoft.

Bus Master IDE driver V3.02 for Windows 95

First read the License Agreement!

Download the driver:bmide_95.exe [592 KB].

Installation instructions and trouble shooting can be found in the read-me file.

Troubleshooting issues can be viewed at Intel's Web site.

Test your Hard Drive for DMA capability

To determine whether your IDE hard disk supports multiple-word DMA protocol, you can test the primary IDE drive and the secondary IDE drive using debug.

To test the primary IDE drive:

  1. Restart the computer. Press the F8 key to get the Windows 95 Startup menu, and then choose Command Prompt Only
  2. At the command prompt, type debug
  3. At the hyphen prompt, type the following lines, pressing Enter after each line. Do not type the comment

    Note: The first character of each line is the letter o, not the numeral zero

    Type Comment
    o 1f6 a0 a0 (a-zero) is for a master drive; use b0 for a slave
    o 1f2 22 22 is for DMA mode 2; use 21 for DMA mode 1
    42 is for UDMA mode 2; use 41 for UDMA mode 1 and 40 for UDMA mode 0
    o 1f1 03 03 (zero-3) is to program the hard disk timing
    o 1f7 ef ef is the set feature command for the hard disk
    i 1f1 Reads in the error status; a value is returned

    If the number returned after entering i 1f1 is 00, the hard disk accepts the DMA protocol timing that you entered with the o 1f2 statement, and the hard disk supports DMA. A return value of 04 indicates that the hard disk does not support a DMA multiple-word protocol. If the value returned is not 00 or 04, you may not have typed the characters correctly, or you may need to quit Windows.

    PIO mode 3 hard disks may support multiple-word DMA mode 1. PIO mode 4 hard disks should support multiple-word DMA mode 2. If you have a PIO mode 4 drive that does not support multiple-word DMA mode 2, it is possible that the hard disk has a firmware problem. Contact the hard disk manufacturer, and verify the firmware version.

  4. To quit Debug, type q and press Enter

To test the secondary IDE drive:

  1. Restart the computer. Press the F8 key to get the Windows 95 Startup menu, and then choose Command Prompt Only
  2. At the command prompt, type debug
  3. At the hyphen prompt, type the following lines, pressing Enter after each line. Do not type the comment

    Note: The first character of each line is the letter o, not the numeral zero

    Type Comment
    o 176 a0 a0 (a-zero) is for a master drive; use b0 for a slave
    o 172 22 22 is for DMA mode 2; use 21 for DMA mode 1
    42 is for UDMA mode 2; use 41 for UDMA mode 1 and 40 for UDMA mode 0
    o 171 03 03 (zero-3) is to program the hard disk timing
    o 1f7 ef ef is the set feature command for the hard disk
    i 171 Reads in the error status; a value is returned

    If the number returned after entering i 171 is 00, the hard disk accepts the DMA protocol timing that you entered with the o 172 statement, and the hard disk supports DMA. A return value of 04 indicates that the hard disk does not support a DMA multiple-word protocol.

    If your drive does support a DMA multiple-word protocol and the DMA check box will not remain enabled, the IDE controller may not be compatible with the Microsoft IDE bus mastering driver.

  4. To quit Debug, type q and press Enter

If you have trouble, start viewing these Microsoft Knowledge Base Articles:


Troubleshooting issues for the Intel INF update and BM-IDE driver can be found at Intel's Web site.

June 23, 2003