In case you haven t realized it, building computer systems is hard. As the complexity of the system gets greater, the task of building the software gets exponentially harder. As in any profession, we can progress only by learning, both from our mistakes and from our successes. This book represents some of this learning written in a form that I hope will help you to learn these lessons quicker than I did, or to communicate to others more effectively than I did before I boiled these patterns down.
著名的AT&T UNIX v6 源碼，雖然已不能在現在的機器中直接運行（通過在Linux上安裝pdp11 simulator可以運行），但從中首先可以學習到C程序設計的簡約與嚴謹（原作者是圖靈獎得主Brian W. Kernighan和Dennis M. Ritchie），其次還可以幫助深入理解操作系統概念，其設計思想仍然廣泛存在于多數操作系統中。
本系統的首次發布于1976年，現仍然做為MIT高年級學生、研究生的操作系統學習的分析材料。
