Windows 95 optimizes the performance of new Win32-based applications and existing applications created for MS-DOS and earlier versions of Windows. They perform more smoothly because Windows 95 significantly increases system resources available to them and more efficiently manages how they use system memory. Windows 95 also supports new and existing versions of OLE technology, including OLE Controls and OLE Automation for new Windows-based applications.
Increased system resources.
Windows 95 increases system resources for all applications by using 32-bit heaps to store applications' data structures, making more resources available for the remaining data elements. In addition, Windows 95 increases the number of timers, COM and LPT ports, Windows menu handles, and other resources available to applications. For more information, see Chapter 17, "Performance Tuning."
Improved memory management.
The Virtual Machine Manager, an integral part of Windows 95 architecture, manages the memory that each application needs. A virtual machine (VM) is an environment in memory that seems to function as a separate computer for each application. All Win32-based and Win16-based applications run in the System VM, in which all system processes also run. Each MS-DOS – based application runs in its own VM. For more information, see Chapter 31, "Windows 95 Architecture."
Win32-based applications receive the full benefit of the performance enhancement features in Windows 95. Because each Win32-based application runs in a separate memory space, it can take complete advantage of the preemptive multitasking capabilities of Windows 95.
Requirements for Windows 95 Logo.
To get the best possible performance, upgrade to versions of applications that were designed for Windows 95 whenever possible. Applications written specifically for Windows 95 carry the "Designed for Windows 95" logo. To qualify for a Windows 95 logo, applications must meet the following requirements:
There are modified requirements for file-based applications, utilities such as anti-virus software, and compilers and other development tools. For more information, contact the Microsoft Developer Network (MSDN). In Canada or the United States, call (800) 759-5474, or in Europe call +31 10 258 88 64.
Win16-based applications designed for Windows 3.1 run under Windows 95 without modification, but these applications run in a shared memory space and cannot take advantage of preemptive multitasking. However, they do benefit from improvements incorporated into the Windows 95 subsystem. For Win16-based and MS-DOS – based applications that are known to need special parameters to run, Windows 95 includes an APPS.INF file that defines parameters for each application.
Because of default settings and other support in Windows 95, you do not need to have CONFIG.SYS, AUTOEXEC.BAT, and INI files to run Win16-based and MS-DOS – based applications, although you can still use settings from existing files. When you upgrade by replacing Windows 3.1 with Windows 95, Windows automatically moves the current settings for your installed applications to the Registry for use with Windows 95.
MS-DOS – based applications can take advantage of the improved memory management and increased system resources that are made possible by the new system architecture. Most applications can now run in a window. MS-DOS – based applications that do not run well under Windows can run the application in exclusive MS-DOS Mode, which makes all system resources available to that application, as described in "Changing Memory Settings for MS-DOS – Based Applications " later in this chapter.
When running under Windows 95, MS-DOS – based applications also benefit from the following: