QIC 40/80 Tape Drives Slow with Adaptec 154x Controller (120812)


The information in this article applies to:

  • Microsoft Windows NT Server 3.1
  • Microsoft Windows NT Workstation 3.1
  • Microsoft Windows NT Advanced Server 3.1
This article was previously published under Q120812

SYMPTOMS

After you configure an Adaptec 154xC or 154xCF SCSI controller for floppy controller support, data transfer on QIC 40/80 tape drives may be slow.

NOTE: If you are using an Adaptec 154xA or 154xB SCSI controller and the performance is slow, upgrade to the Adaptec 154xC or 154xCF and change the busontime/busofftime values, if necessary.

CAUSE

This problem occurs on ISA-based machines when devices that use floppy controllers contend for DMA time with devices that use SCSI controllers. EISA-based machines do not have this problem because they have a built-in DMA arbitrator circuit.

RESOLUTION

Download 1542CCFG.ZIP from Adaptec's BBS at (408) 945-7727. After you extract the files, follow these steps:

  1. Boot your machine and press CTRL+A when the system is verifying and running the SCSI configuration. This allows you to run the SCSISELECT utility in the MS-DOS environment.
  2. Select MS-DOS at the Windows NT flexboot option, or place an MS-DOS boot disk in drive A. Follow Step 1 again.
  3. In conjunction with the utility, run C_CONFIG.EXE if you have an Adaptec 1542C or CF_CONFIG.EXE if you have an Adaptec 1542CF.

    NOTE: C_CONFIG.EXE and CF_CONFIG.EXE are available after extracting 1542CCFG.ZIP.
  4. In Advanced Configuration, set the values of:

    BusOnTime to 4 microseconds
    BusOffTime to 12 microseconds

  5. Exit the utility program and restart your system.

STATUS

The product discussed here is manufactured by Adaptec, a vendor independent of Microsoft; we make no warranty, implied or otherwise, regarding this product's performance or reliability.
Modification Type:MajorLast Reviewed:11/20/2003
Keywords:KB120812
©2003 Microsoft Corporation. All rights reserved.