Macintosh: Where Changes Are Stored When a File Is Edited



For security reasons, I need to know where changes stored during editing of
a document. Is there a temporary document created, or are the changes
stored in RAM until I save or exit the document?

How a document stores changes varies depending on the manufacturer. For
instance, MacPaint is a "RAM based" program and keeps its "changes" in the
application heap space. MacPaint saves changes to disk only when you choose
Save, whereas Microsoft Word buffers data to the disk.

Generally, if your program is creating "temp" files, it is writing changes
to disk. For instance, with MultiFinder running, launch Microsoft Word and
note how it creates a Word Temp file in the System folder. Quit Microsoft
Word (saving your document using Save or Save As) and the "Word Temp" file
disappears. Not all temp files are visible, and some applications may
buffer data to disk without being so obvious.

If you must know if an application buffers user data to disk, ask the
manufacturer of your software.

A related issue is the Virtual INIT and Virtual in System 7. By design,
both programs buffer data to disk (but you have the option to turn them
off).


Published Date: Feb 18, 2012