Source string Read only

(itstool) path: answer/para
Context English State
<prompt>#</prompt> <userinput>boot0cfg -B ada0</userinput>
The non-interactive MBR bootloader can be installed using <citerefentry><refentrytitle>gpart</refentrytitle><manvolnum>8</manvolnum></citerefentry>:
<prompt>#</prompt> <userinput>gpart bootcode -b /boot/mbr ada0</userinput>
For more complex situations, including GPT disks, see <citerefentry><refentrytitle>gpart</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
Do I need to install the source?
In general, no. There is nothing in the base system which requires the presence of the source to operate. Some ports, like <package>sysutils/lsof</package>, will not build unless the source is installed. In particular, if the port builds a kernel module or directly operates on kernel structures, the source must be installed.
Do I need to build a kernel?
Usually not. The supplied <literal>GENERIC</literal> kernel contains the drivers an ordinary computer will need. <citerefentry><refentrytitle>freebsd-update</refentrytitle><manvolnum>8</manvolnum></citerefentry>, the FreeBSD binary upgrade tool, cannot upgrade custom kernels, another reason to stick with the <literal>GENERIC</literal> kernel when possible. For computers with very limited RAM, such as embedded systems, it may be worthwhile to build a smaller custom kernel containing just the required drivers.
Should I use DES, Blowfish, or MD5 passwords and how do I specify which form my users receive?
FreeBSD uses <emphasis>SHA512</emphasis> by default. DES passwords are still available for backwards compatibility with operating systems that still use the less secure password format. FreeBSD also supports the Blowfish and MD5 password formats. Which password format to use for new passwords is controlled by the <literal>passwd_format</literal> login capability in <filename>/etc/login.conf</filename>, which takes values of <literal>des</literal>, <literal>blf</literal> (if these are available) or <literal>md5</literal>. See the <citerefentry><refentrytitle>login.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> manual page for more information about login capabilities.
What are the limits for FFS file systems?
For FFS file systems, the largest file system is practically limited by the amount of memory required to <citerefentry><refentrytitle>fsck</refentrytitle><manvolnum>8</manvolnum></citerefentry> the file system. <citerefentry><refentrytitle>fsck</refentrytitle><manvolnum>8</manvolnum></citerefentry> requires one bit per fragment, which with the default fragment size of 4 KB equates to 32 MB of memory per TB of disk. This does mean that on architectures which limit userland processes to 2 GB (e.g., <trademark>i386</trademark>), the maximum <citerefentry><refentrytitle>fsck</refentrytitle><manvolnum>8</manvolnum></citerefentry>'able filesystem is ~60 TB.
If there was not a <citerefentry><refentrytitle>fsck</refentrytitle><manvolnum>8</manvolnum></citerefentry> memory limit the maximum filesystem size would be 2 ^ 64 (blocks) * 32 KB =&gt; 16 Exa * 32 KB =&gt; 512 ZettaBytes.
The maximum size of a single FFS file is approximately 2 PB with the default block size of 32 KB. Each 32 KB block can point to 4096 blocks. With triple indirect blocks, the calculation is 32 KB * 12 + 32 KB * 4096 + 32 KB * 4096^2 + 32 KB * 4096^3. Increasing the block size to 64 KB will increase the max file size by a factor of 16.
Why do I get an error message, <errorname>readin failed</errorname> after compiling and booting a new kernel?
The world and kernel are out of sync. This is not supported. Be sure to use <command>make buildworld</command> and <command>make buildkernel</command> to update the kernel.
Boot the system by specifying the kernel directly at the second stage, pressing any key when the <literal>|</literal> shows up before loader is started.
Is there a tool to perform post-installation configuration tasks?
Yes. <application>bsdconfig</application> provides a nice interface to configure FreeBSD post-installation.
Hardware Compatibility
I want to get a piece of hardware for my FreeBSD system. Which model/brand/type is best?
This is discussed continually on the FreeBSD mailing lists but is to be expected since hardware changes so quickly. Read through the Hardware Notes for FreeBSD <link xlink:href="">12.1</link> or <link xlink:href="">11.3</link> and search the mailing list <link xlink:href="">archives</link> before asking about the latest and greatest hardware. Chances are a discussion about that type of hardware took place just last week.
Before purchasing a laptop, check the archives for <link xlink:href="">FreeBSD general questions mailing list</link>, or possibly a specific mailing list for a particular hardware type.
What are the limits for memory?
FreeBSD as an operating system generally supports as much physical memory (RAM) as the platform it is running on does. Keep in mind that different platforms have different limits for memory; for example <trademark>i386</trademark> without <acronym>PAE</acronym> supports at most 4 GB of memory (and usually less than that because of PCI address space) and <trademark>i386</trademark> with PAE supports at most 64 GB memory. As of FreeBSD 10, AMD64 platforms support up to 4 TB of physical memory.
Why does FreeBSD report less than 4 GB memory when installed on an <trademark>i386</trademark> machine?
The total address space on <trademark>i386</trademark> machines is 32-bit, meaning that at most 4 GB of memory is addressable (can be accessed). Furthermore, some addresses in this range are reserved by hardware for different purposes, for example for using and controlling PCI devices, for accessing video memory, and so on. Therefore, the total amount of memory usable by the operating system for its kernel and applications is limited to significantly less than 4 GB. Usually, 3.2 GB to 3.7 GB is the maximum usable physical memory in this configuration.
To access more than 3.2 GB to 3.7 GB of installed memory (meaning up to 4 GB but also more than 4 GB), a special tweak called <acronym>PAE</acronym> must be used. PAE stands for Physical Address Extension and is a way for 32-bit x86 CPUs to address more than 4 GB of memory. It remaps the memory that would otherwise be overlaid by address reservations for hardware devices above the 4 GB range and uses it as additional physical memory (see <citerefentry><refentrytitle>pae</refentrytitle><manvolnum>4</manvolnum></citerefentry>). Using PAE has some drawbacks; this mode of memory access is a little bit slower than the normal (without PAE) mode and loadable modules (see <citerefentry><refentrytitle>kld</refentrytitle><manvolnum>4</manvolnum></citerefentry>) are not supported. This means all drivers must be compiled into the kernel.
The most common way to enable PAE is to build a new kernel with the special ready-provided kernel configuration file called <filename>PAE</filename>, which is already configured to build a safe kernel. Note that some entries in this kernel configuration file are too conservative and some drivers marked as unready to be used with PAE are actually usable. A rule of thumb is that if the driver is usable on 64-bit architectures (like AMD64), it is also usable with PAE. When creating a custom kernel configuration file, PAE can be enabled by adding the following line:
options PAE


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(itstool) path: answer/para
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a year ago
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a year ago
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books/faq.pot, string 227