Large Disk Problems and Solutions, Part 1

By: Walter Metcalf
Date: 06/07/00

A large number of people have contacted me recently regarding problems with new hard drives. Upon investigation, most of these people's problems are variations on the same theme. This series deals with the underlying issues to those problems, and gives solutions where available.

Software Problems


  1. Age

    1. OS/2 Warp 4 Client was released in 1996, in the days when hard drives were still measured in megabytes! While the disk drivers have been modified and released to keep pace with the phenomenal growth of disk technology, FDISK and BOOT MANAGER, OS/2's chief partition management tools, have not.

    2. FDISK has no facility for resizing partitions, which is even more problematic in these days of large gigabyte drives. Backing up a 35 GB hard drive to tape, re-partitioning, and restoring the drive from tape is no longer a viable option. Consequently OS/2 users are forced to rely on a third-party manufacturer to meet this important need.

    3. PowerQuest has been the only manufacturer to produce a standalone product--Partition Magic--capable of performing resizing, moving, and related operations on partitions. Versions 3.0 and earlier of Partition Magic did not support for disk drives > 4 GB. Subsequent versions contained support for larger drives, but no longer contained OS/2 code. Support for HPFS partitions, however, has remained through version 5.0.

  2. Specific Software Components

    1. FDISK

      1. Filesystems When Warp 4 was released, FDISK could "see" all of the DOS-based filesystems available at that time plus, of course, HPFS. (The FAT32B system of the later Windows 95 systems and Windows 98 had not been released.) When FAT32B was later released by Microsoft, FDISK was never updated to handle it properly.

      2. Drive Letters FDISK cannot tell whether a drive letter has been or will be assigned to a FAT32 partition.

      3. Extended Partition In a move typical of the company, Microsoft changed from the standard Extended (Type 05) to a proprietary "ExtendedX" (Type 0F) once the size of the extended partition reached 1024 cylinders. This can result in disks partitioned with the Windows version of Partition Magic 5.0 being unusable by OS/2.

      4. As a result of the above factors, FDISK and BootManager display FAT32B partitions inconsistently, depending on the exact version software involved, size of the partitions, etc. In fact when a FAT32B partition is present, BootManager is likely to display the many of the the other partitions incorrectly as well.

        1. For example my notebook has DOS FAT16 (Drive C:) (Hidden), Windows 98 FAT32B (Drive C:), Warp 4 HPFS main, (Drive D:) and a Warp HPFS maintenance (Drive E:) partitions. Here is what Boot Manager displays:

          Boot Manager
          2.1 2.2 2.3 2.4 2.5
          DOS Disk 1 C:Primary 201M FAT (hidden)
          Win 98 Disk 1 Primary 847M Type 0F
          Warp 4 Disk 1 C:Logical 327M HPFS
          Maint Disk 1 D:Logical 52M HPFS

        2. Note that three partitions have incorrectly assigned the letter C: with the result that the two OS/2 partitions are now unbootable because they have the wrong drive letter! Moreover, the Win 98 partition has not been assigned a drive letter because it is not visible to Boot Manager, yet is a bootable partition. Even the DOS partition is incorrect, because according to FDISK/Boot Manager logic, a hidden partition should not have a drive letter. Every one of the four partitions is incorrect in one way or another!

        3. The presence of a FAT32B partition often renders a Boot Manager unstable. For example, in the case shown above, if I select DOS from the menu and press <Enter> to select the DOS partition (which works even though hidden), and then reboot to display the the Boot Manager menu, the drives letters will have changed so that the OS/2 drives will be bootable. However attempting to boot from the Win 98 partition will fail.

    2. Drivers

      A very common source of problems is out-of-date drivers.

      1. The disk drivers that originally came with Warp 4 could only support 528MB. 1 Larger drives required special BIOSes or BIOS translation utilities.

      2. Unlike FDISK/BootManager, however, the disk drivers have been updated to keep pace with rapidly developing disk technology. The latest driver updates are in the file, IDEDASD, which is kept in the IBM Device Driver Pak On-line.

        1. Complete instructions for installing the drivers are contained in a Readme file included in the IDEDASD file.

        2. TIP: It is VERY important to update your installation and boot diskettes as well. Failure to do so will cause your hard drive to be overwritten with the obsolete drivers the next time the diskettes are used. The drivers in question are IBM1S506.ADD, IBMIDECD.FLT and OS2DASD.DMD; use these files to update Installation Diskette 1 (i.e. the 2nd diskette of the 3-diskette set)
Next Week we'll look at how some third-party products can be used to solve some of these problems. Stay tuned!

Walter Metcalf

For Further Reading:

Large Disks: How OS/2 Uses Them, Part 1
My previous series on the subject that still contains much good basic material.

Partition Tables
Learn all about the Master Partition Table

Next week: Large Disk Problems and Solutions, Part 2


1 OS/2 Warp 4: Up and Running! p.83

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