Performance Tuning Overview

The Windows 98 architecture includes performance improvements over earlier versions of Windows. The changes, which strongly impact most areas of system performance, are as follows:

• 32-bit device drivers for all system components, ensuring better performance and better resource management.
• An application launch accelerator that uses Disk Defragmenter to optimize disks for quicker start of applications.
• Optimization for new Advanced Configuration and Power Interface (ACPI) computers with fast-boot basic input/output system (BIOS) support.
• Quicker system shutdown than with Windows 95.
• More efficient memory management with MapCache and lazy swap file writing.
• OnNow, which causes the computer to go into a low-power mode when not in use and to quickly start up when needed.

  For more information about OnNow, see Chapter 30, "Hardware Management."

Many Windows 98 features provide dynamic configuration, reducing or eliminating the need for users to adjust system settings. The following self-tuning features in Windows 98 are designed to improve performance and reduce support costs.

Dynamic swap file and dynamic caching using VCACHE.

VCACHE is a 32-bit protected-mode cache driver. Windows 98 uses dynamic sizes for the virtual memory swap file, the cache for file and network access, and the CD-ROM cache. Both the swap file and cache sizes can grow or shrink, depending on the computer’s memory configuration and the demand for memory from applications. This relieves users or administrators from having to change the cache parameters as new memory or new applications are added. Windows 98 can take advantage of new memory automatically and expand or reduce the file and cache sizes automatically based on demands when applications are loaded or unloaded. Because in Windows 98 some code is executed out of cache, cache sizes are larger in Windows 98 than they were in Windows 95 (the MapCache feature). Also, the networking, disk, CD-ROM, and paging caches are integrated and scale as more memory is added to the computer. For more information, see "Optimizing the Swap File" and "Optimizing File System Performance" later in this chapter.

Note

Windows 98 does not delete an existing swap file on the boot drive during system boot, because that file automatically shrinks if it is not being used. This keeps system boot time to a minimum.

A user might see a large Win386.swp file immediately after system boot. This could be due to the system being stressed during the previous session; it has nothing to do with the current session.

32-bit disk and file access for fast hard disk access.

These mechanisms allow Windows 98 to access the hard disk or file system directly, bypassing the computer’s BIOS. Using 32-bit file and disk access improves performance and allows Windows 98 to handle BIOS requests in protected mode rather than in real mode. For more information, see Chapter 10, "Disks and File Systems."

Background print rendering.

For a computer that has sufficient memory to take advantage of it, background print rendering is available automatically to reduce the return-to-application time for printing. With this feature, Windows 98 first writes an enhanced metafile (EMF) format file, which is a device-independent rendering of the print job that is much faster to produce than a device-specific rendering. In the background, Windows 98 uses the EMF file to create the device-dependent rendering while the user continues to work in the application. For more information, see "Optimizing Printing" later in this chapter.

Automatic system adjustments during Windows 98 Setup.

During installation, Windows 98 Setup makes decisions about certain operating system features based on the hardware configuration. For example, in a computer with low memory, Windows 98 turns off background print rendering, because this feature increases the operating system working set that is loaded into memory and cannot be paged out to the swap file.

Built-in tools for monitoring and adjusting system performance.

The following tools in Windows 98 are available for managing performance-related settings:

• The Maintenance Wizard is used to schedule several performance-improving tasks, such as Disk Defragmenter, ScanDisk, Disk Cleanup, and Compression Agent (on DriveSpace3 drives). You can:
  • Speed up frequently used programs.
  • Check the hard disk for errors.
  • Delete unnecessary files from the hard disk.
  • Remove programs from the Startup group.

  For more information about Maintenance Wizard, see Chapter 27, "General Troubleshooting," and Chapter 10, "Disks and File Systems."

  For more information about Disk Defragmenter, ScanDisk, and Disk Cleanup, see Chapter 10, "Disks and File Systems."

• System option in Control Panel provides settings for tuning and troubleshooting. For information, see "Optimizing the Swap File," "Optimizing File System Performance," and "Setting Graphics Compatibility Options" later in this chapter.
• System Monitor can be used to track the performance of key system components, as described in "Tracking Performance with System Monitor" later in this chapter.
• DriveSpace includes a protected-mode driver that is installed by default, providing faster performance than the earlier real-mode compression driver and using only an additional 10 or 15 percent overhead. If you are using any real-mode disk-compression utilities other than DriveSpace or DoubleSpace, plan to switch to a protected-mode version. Contact the manufacturer to determine availability of protected-mode drivers that are compatible with Windows 98.

  Note

  A FAT32 volume cannot be compressed using Microsoft DriveSpace3.

• Disk Defragmenter can improve file access time by defragmenting uncompressed file allocation table (FAT) drives and compressed DriveSpace or DoubleSpace drives. Fragmentation occurs over time, as programs read from and write to the hard disk. Eventually, files must be stored in noncontiguous sectors on a disk. Fragmentation does not affect the validity of the information, but it takes much longer for the computer to read and write fragmented files. In addition, there is an application launch accelerator that uses Disk Defragmenter to optimize disks for quicker start of applications.
• Registry Checker is a system maintenance program that finds and fixes registry problems. Each time you start the computer, Registry Checker automatically scans the registry for inconsistent structures, and if no problem is found, it backs up the registry once a day. If a problem is found in the registry, Registry Checker can restore the registry from a good backup copy (Registry Checker generally maintains a set of registry backups that have successfully started the computer). If, for some reason, a backup cannot be found, Registry Checker will attempt to fix the registry. Registry Checker also removes unused space in the registry, reducing the size of the registry file and thus improving performance.
• Scheduled Tasks Wizard lets you run useful utilities and routine tasks at regular intervals. You can set the tasks to run at times that are most convenient for you. Each task can be reconfigured once it has been set up. Task configuration parameters include:
  • Source location of the program.
  • Frequency, date, and time that the program should be run.
  • When to delete or stop the program.
  • How to run the program if the computer is idle, is in use, or has power management options enabled.
• WinAlign is a tool that allows greater use of the MapCache feature, which optimizes memory usage and general system performance.