Quotas are enforced to address potential denial of service problem of isolated storage from a malicious or buggy site wasting or filling up the system disk space. All quotas are in bytes.
Quotas apply to bytes of file space as well as a “byte cost” (may exceed actual storage consumption of the implementation, but should never underestimate) for directory and other information retained within the store.
Quotas will be conservatively rounded off to a block size. Block size is used to speed up allocation and quota management. The block size is implementation dependent.
These quotas apply to all uses of isolated storage; an attempt to write data that exceeds any applicable quota will result in an exception. Permissions may further limit sizes for certain code, but can never allow code to exceed established administrative quotas.
See section 3.1 on how the machine administrator can configure these.
Quota granted in permissions further restrict specific code, up to be not exceeding administrative quota.
Note: a single entity may use any number of distinct site or signature identities so these quota are merely a guideline for well-behaved use of the feature; the global store limits are what truly enforce against malicious denial of service attacks.