This article is from the Apple II GNO FAQ, by Devin Reade with numerous contributions by others.
A#1.4: The GNO documentation specifies that the minimum requirement is an Apple IIGS with 1.25 MB of memory and a 3.5" disk drive. Realistically (especially with all the third-party add-ons), a hard drive (or other large mass storage device) should be considered a necessity. An accelerator and additional memory is recommended. There is not an official "minimum disk space" requirement as yet. When this information becomes available, it will be added to this FAQ.
 
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