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Existing Applications

Existing applications could be ported easily using:

• pessimistic: fopen(name,mode) $\rightarrow$ p_open(name,mode,$\infty$) or using p_lock(name,mode,$\infty$)
• strict: fopen(name,mode) $\rightarrow$ p_open(name,mode,0)
• optimistic: fopen(name,mode) $\rightarrow$ p_open(name,mode,-$\infty$)

Note: The $\infty$ in the above read-statements means a sufficiently large number (so big that it will last the whole of the systems lifetime).

Default values for $CT \! B$, $MT \! B$, and $ET \! B$ pr. system or application could be used implicitly when running existing applications (unchanged). However this would require new daemons to catch, for instance, access to remote files via NFS, e.g. as it is done in [32].

Figure 5.9: Example use of transactions (1)

Figure 5.10: Example use of transactions (2)