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@@ -2,28 +2,29 @@
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<title>About SBUs</title>
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<?dbhtml filename="aboutsbus.html" dir="chapter02"?>
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-<para>SBUs are <emphasis>Static Bash Units</emphasis> and they are our way
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-of identifying how long a package takes to compile. Why don't we use normal
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-times like anybody else?</para>
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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>The biggest problem is that times cannot be accurate, not even a
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-little bit. So many people install LFS on so many different systems, the
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-times it takes to compile something varies too much. One package may take
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-20 minutes on one system, but that same package may take 3 days on another
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-(this is not an exaggeration). So instead we've come up with a
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-<emphasis>Static Bash Unit</emphasis> or <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>It works like this: the very first package you compile in this book
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-is Bash in Chapter 5 and it'll be statically linked. The time it takes to
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-compile this package will be the basis and called the SBU. All other
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-compile times are relative to the time it takes to install Bash. For
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-example, GCC-3.2 takes about 9.5 SBUs and it's proven that this number is
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-fairly consistent among a lot of different systems. So multiply 9.5 by the
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-number of seconds it takes for Bash to install (the SBU value) and you get
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-a close approximation of how long GCC will take on your system.</para>
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+<para>For example, the time it takes to build the static version of GCC is 3.9
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+SBU. This means that if on your system it took 10 minutes to compile and
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+install the static Binutils, then you know it will take nearly 40 minutes to
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+build the static GCC. Fortunately, most build times are much shorter than the
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+one of Binutils.</para>
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-<para>Note: We've seen that SBUs don't work well on SMP based machines. So
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-all bets are off if you're lucky enough to have an SMP setup.</para>
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+<para>Note that SBUs don't work well for SMP-based machines. But if you're so
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+lucky as to have multiple processors, chances are that your system is so fast
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+that you don't mind.</para>
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</sect1>
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Alex Gronenwoud