This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
Yes. Today, most "DOS 3.3 users" do not actually use DOS 3.3. Long ago, Beagle Bros introduced patches which resulted in much better speed, freed-up extra disk space, and added a CATALOG command which shows number of Free Sectors. Their Prontodos or some modification of it is, for practical purposes, the "current version" of DOS 3.3. ES DOS ][ adds a few mods to Prontodos. CATALOG shows Free Sectors and Number of Tracks and it scrolls the entire Catalog (scrolling stopped by pressing any key) instead of stopping when the screen is full. ES DOS ][ also lets you use the semi-colon as a terminating 'wildcard' character. This DOS includes a CATALOG fix to show correct size of files bigger than 255 sectors. Other popular, higher speed versions of DOS 3.3 include David DOS and Diversi-DOS; and, there are several small, special-purpose versions of DOS 3.3. (For example, one game maker used RDOS to save space and to make its diskettes harder to copy.) Below is a chart which compares speed and features for standard and speeded versions of DOS 3.3. BLOAD Time Does Large Files Frees 15 Disp Free Error Test*** INIT CATALOG fix Sectors Sectors Msg Std DOS 3.3**- 8.9 sec Yes No No No Yes DavidDOS- 2.8 sec No Yes No Yes Yes DiversiDOS- 2.9 sec Yes Yes No Yes err# EsDOS- 2.3 sec Yes Yes Yes Yes abbr* ProntoDOS v1- 3.0 sec Yes No Yes No Yes ProntoDOS v2- 3.0 sec Yes No Yes Yes Yes abbr: shows abbreviated error messages * 1980-1983 versions *** time to BLOAD MUFFIN from the 1983 DOS 3.3 System Master disk You can get standard and high-speed DOS 3.3's from a number of places on the net. See Csa21MAIN4: Get It- Links to popular software packages. -----------------------