Question:

I installed a new disk drive and now CHKDSK traps when attempting to AUTOCHECK after a dirty shutdown. How do I fix this?

Answer:

You did not mention the size of the new disk drive and the partitions, but most likely the drive is large and you created one or more large HPFS volumes or partitions.

Under normal conditions, when the HPFS AUTOCHECK logic invokes CHKDSK at boot time, the kernel is still initializing the system and the virtual memory subsystem is not fully initialized. This limits the amount of memory available to CHKDSK and an attempt to CHKDSK a large partition will fail.

You have several options that will allow CHKDSK to run successfully:

• Use CHKDSK.SYS.
• Run CHKDSK with /C option.
• Use the EARLYMEMINIT kernel option.
• Use JFS volumes.

Use CHKDSK.SYS

CHKDSK.SYS is base device driver which runs early in the boot process and allocates memory that CHKDSK can use during AUTOCHECK.

To use CHKDSK.SYS add:

  BASEDEV=CHKDSK.SYS

The downside of using CHKDSK.SYS is that you will be forced to reboot after the AUTOCHECK completes. However, if your setup requires access to files on large partitions to boot correctly, your choices are limited.

Run CHKDSK with the /C option

CHKDSK can be run from CONFIG.SYS. With the /C option, CHKDSK will bypass the full scan unless the drive is marked dirty.

This is a good method for checking large data volumes or partitions that are not otherwise accessed before the PM and the WPS start up.

To use this method, add the line:

  CALL=x:\OS2\CHKDSK.COM y: /F /C

Use the EARLYMEMINIT kernel option.

The EARLYMEMINIT option changes the kernel behavior so that the virtual memory subsystem is fully initialized before the CHKDSK AUTOCHECK logic runs.

This option does not work on all systems and is considered somewhat experimental. The other options are usually a better choice.

To use the EARLYMEMINIT option, add the statement:

  EARLYMEMINIT=TRUE

Use JFS volumes.

The JFS file system, unlike the HPFS file system, does not have problems checking large volumes at boot time. JFS volumes also CHKDSK much faster. JFS also supports much large cache sizes which improves overall performance.

The only real downside of JFS compared to HPFS, for most users, is that the IFS code is young compared to the HPFS code. There were some reports of data loss with early releases of JFS.IFS, but the current releases appear to be as solid as HPFS.IFS.

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