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ArtistA beautiful purple-haired woman wearing a long purple velvet ankle-length dress with flouncy sleeves and purple suede high heels. She is pointing to several suitcases and items of luggage around her.
For security reasons, each thread in ::SHE+ILA:: runs under a specific User Account. The Account is owned by the Kernel (SHE -- Segmented Hierarchical Environment) and (among other things) contains a list of valid LBA's accessible to any thread running under this Account. This prevents unauthorised access to all other Segments in the Store. User Accounts are not programatically modifiable by any user, but can only be created manually by the System Administrator. They are held in a special part of the DataStore in an encrypted format. Every thread must specify the User Account that it runs under (see GHOST -- Global Hosting Online Segment Table), using the Pound ("£") operator, for example :
£::DEMO::
main <:: {ttyout ("Hello World", CRLF)};
Since the User Account contains its own GHOST, i.e. list of segment names authorised for this User, we no longer need to also specify them at the start of the program. For example, both Users ::GUEST:: and ::DEMO:: are authorised to access segments ::MATHS:: and ::UTILS::
The absence of a User Account at the top of a program will default to User ::GUEST::, which has absolutely minimum privileges.
Each User Account can access a maximum of 99 Segments simultaneously (the Address opcode contains a single byte BCD SegID field), and each User Account specifies a MAXPAGES datastore quota in order to prevent excessive spurious datastore usage consuming all the disk space. A total CPU usage quota can also be specified, to avoid machine hogging. Flags grant or deny certain peripheral access by any thread running under the Account (e.g. internet usage, telephony usage, soundcard and graphics usage).
These restrictions can be worked round where absolutely necessary by means of message-passing (Buf insert and extract) to another thread running under a more privileged account.
