1 . 3
D E S I G N C O N S T R A I N T S
5
9 GB drive because of file system limits. All these factors pointed to the need
for a 64-bit-capable file system.
In addition to the above design goals, we had the long-standing goals of
making the system as multithreaded and as efficient as possible, which meant
fine-grained locking everywhere and paying close attention to the overhead
introduced by the file system. Memory usage was also a big concern. We did
not have the luxury of assuming large amounts of memory for buffers because
the primary development system for BFS was a BeBox with 8 MB of memory.
1.3
Design Constraints
There were also several design constraints that the project had to contend
with. The first and foremost was the lack of engineering resources. The Be
engineering staff is quite small, at the time only 13 engineers. Cyril and I had
to work alone because everyone else was busy with other projects. We also
did not have very much time to complete the project. Be, Inc., tries to have
regular software releases, once every four to six months. The initial target
was for the project to take six months. The short amount of time to complete
the project and the lack of engineering resources meant that there was little
time to explore different designs and to experiment with completely untested
ideas. In the end it took nine months for the first beta release of BFS. The final
version of BFS shipped the following month.
1.4
Summary
This background information provides a canvas upon which we will paint
the details of the Be File System. Understanding what the BeOS is and what
requirements BFS had to fill should help to make it more clear why certain
paths were chosen when there were multiple options available.
Practical File System Design:The Be File System
, Dominic Giampaolo
page 5
Summary :
In addition to the above design goals, we had the long-standing goals of making the system as multithreaded and as efficient as possible, which meant fine-grained locking everywhere and paying close attention to the overhead introduced by the file system. Practical File System Design:The Be File System , Dominic Giampaolo page 5
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