ABSTRACT
The TRANSFER BOTH does the following. The transaction first attempts to enter the Block with the label (first label); if it can,
it does so; if it cannot, it attempts to enter the Block with the label (second label). If it can, it does so; if not, it resides in the TRANSFER Block until some later time when it can enter the next Block. If the label (first) is omitted (99% of the time it will be), it is assumed that the transaction tries to enter the next sequential Block. For example, suppose a person tries to enter a shop with a single chair to sit in. If the chair is occupied, the person leaves the shop. Consider the following:
TRANSFER BOTH,CHAIR,AWAY CHAIR SEIZE SITDOWN ………. ………….. AWAY TERMINATE
The above normally would be written as follows:
TRANSFER BOTH,,AWAY SEIZE SITDOWN …………. ……………….. AWAY TERMINATE
Example 15.1: Repairing Equipment in a Mine
A mine has a machine that repairs parts in 38 ± 10 minutes. A new addition to the mine means the broken equipment will arrive at 20 ± 8 minute intervals, so the old machine cannot keep up with the repairs. A new machine is going to be purchased that will work at a rate of 32 ± 9 minutes. This, still, will not be fast enough to repair the broken parts, so the old machine will be kept but put into use only when the new machine is busy. A broken part always tries to use the new machine. Determine how busy the new and old machines will be. Here we have a situation where an ENTER Block cannot be used as the repair machines work at different rates. Simulate for 20 shifts of 480 minutes.
