mirror of https://github.com/tLDP/LDP
37 lines
1.8 KiB
XML
37 lines
1.8 KiB
XML
<sect1 id="ch02-aboutsbus">
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<title>About SBUs</title>
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<?dbhtml filename="aboutsbus.html" dir="chapter02"?>
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<para>Most people would like to know beforehand how long it approximately
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takes to compile and install each package. But "Linux from Scratch" is built
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on so many different systems, it is not possible to give actual times that are
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anywhere near accurate: the biggest package (Glibc) won't take more than
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twenty minutes on the fastest systems, but will take something like three days
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on the slowest -- no kidding. So instead of giving actual times, we've come up
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with the idea of using the <emphasis>Static Binutils Unit</emphasis>
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(abbreviated to <emphasis>SBU</emphasis>).</para>
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<para>It works like this: the first package you compile in this book is the
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statically linked Binutils in Chapter 5, and the time it takes to compile this
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package is what we call the "Static Binutils Unit" or "SBU". All other compile
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times will be expressed relative to this time.</para>
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<para>For example, the time it takes to build the static version of GCC is
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&gcc-time-tools-pass1;s. This means that if on your system it took 10 minutes
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to compile and install the static Binutils, then you know it will take
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approximately 45 minutes to build the static GCC. Fortunately, most build times
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are much shorter than the one of Binutils.</para>
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<para>Note that if the system compiler on your host is GCC-2 based, the SBUs
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listed may end up being somewhat understated. This is because the SBU is based
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on the very first package, compiled with the old GCC, while the rest of the
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system is compiled with the newer GCC-&gcc-version; which is known to be
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approximately 30% slower.</para>
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<para>Also note that SBUs don't work well for SMP-based machines. But if you're
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so lucky as to have multiple processors, chances are that your system is so fast
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that you won't mind.</para>
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</sect1>
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