Hardware and software specification, acquisition, installation, and maintenance are done on a case by case basis. Most products that are designed to be used by UNIX either operate on standard interfaces, or come with software designed to interface with UNIX. An important part of the administrator's job is to make sure the interface to UNIX will operate.
Another major systems administration task is tuning tunable parameters. This was described in some detail earlier, and we will not elaborate further here.
Performing backups is relatively automatic in the sense that a menu system is provided to automate the typing of commands related to the backup, but people still have to do the backups and test them to assure that they are working properly. Periodic tape head cleaning is required in order to keep backups reliable. Off site copies of backups are important in case of flood, fire, or theft.
Disaster recovery programs should be in place and tested periodically to assure that operation can be restored in case of emergency. Simply having a plan is inadequate, because most sites find that the plan doesn't work unless it has been thoroughly tested.
Interfacing with networks and external systems is the source of many horror stories. UNIX administration facilities are particularly obscure for the ``uucp'' facility, and require laborious trial and error combined with a lot of reading, but once they are working, they only have to be periodically monitored and managed. Other networking systems are equally complex to manage.
Assuring proper delivery of mail and other system provided services takes a considerable amount of administration effort. One of the major problems comes from errors in these services that are not detected early. A good systems administrator will not wait for problems, but rather will have an ongoing set of tests that tend to find problems before the users become aware of them. As procedures become well known, they can often be automated to a large degree, and then only the proper operation of the automation has to be tested.
Periodic checking and clearing of audit trails is very important, since these tend to grow without bound if left unattended. Again, the these operations are often automated by the more skilled systems administrator.
Setting up terminals and other peripheral devices for users grows with the number of users. A good rule of thumb is four terminal setups or changes per year per user, but this varies greatly.
Setting up and maintaining system deamons, controlling the facilities they provide, and providing interfaces to those services for users can be a big job if the systems administrator is responsible for these services and if a lot of services are expected from the system.
Interacting with vendors and maintenance personnel is another important administrative job. In most cases, maintenance and vendor personnel will do the easiest thing they can do to get their job done, but it may not be the best thing for your system. You have to watch and manage them in order to get the best results.
Setting up and maintaining system service Uids is another common administrative task. Setting up these Uids is vital to system protection, but is often not done because of ignorance or laziness by the systems administrator.
Protection administration, at a minimum, consists of assuring that the attacks we discussed earlier are protected against to a degree appropriate for the environment.