* Exclusion: At most one process executes its critical section at any time.

Mutual exclusion is a topic that Leslie Lamport has returned to many times throughout his career. This article, which is being written in celebration of Lamport's sixtieth birthday, is an attempt to survey some of his many contributions to research on this topic.

The (n; k; l)-renaming problem requires that names from the set f1; : : : ; lg are assigned to processes from a set of size n, provided that no more than k l processes are simultaneously either holding or trying to acquire a name. A solution to this problem supplies a renaming object supporting both acquire and release operations so that no two processes ever simultaneously hold the same name. The protocol is waitfree if each participant successfully completes either operation in a bounded number of its own steps regardless of the speed of other processes; it is long-lived if it there is no bound on the number of operations that can be applied to the object; it is fast if the number of steps taken by any process before it completes an operation is independent of n; and it is name-spac...

60dB 4.20 512 96 ETSI-A ETSI-A ETSI-1 60dB 4.20 1536 512 AWGN-140 AWGN-140 Draft Recommendation G.992.2 140 14 T1.601 #9 1536kbps 256kbps 49 Annex A G.992.2 15 T1.601 #9 1536kbps 256kbps 24 DSL 16 Shortened T1.601#7 1536kbps 256kbps 24 HDSL Table 47. Extended Reach Test Cases NOTE1: A goal of future enhancements of this Recommendation is to make the "Extended Reach Cases" mandatory. NOTE2: Performance levels do not reflect the effect of customer premise wiring, which is expected to reduce data rate.G.992.2G.992.2G.992.2 Draft Recommendation G.992.2 139 ANNEX D D.1 System Performance for North America All test loops specified in this section shall be used for G.992.2 and testing shall confirm to the following: . No power cutback on upstream transmitter. . Margin=4 dB . BER=10 -7 . Background noise = -140 dBm/Hz . Rates, except where noted,