nl/hardware/supported-peripherals.xml

<!-- retain these comments for translator revision tracking -->
<!-- $Id: supported-peripherals.xml 11568 2004-03-21 12:12:18Z waldi $ -->

 <sect1 id="supported-peripherals">
 <title>Peripherals and Other Hardware</title>
<para>

Linux supports a large variety of hardware devices such as mice,
printers, scanners, PCMCIA and USB devices.  However, most of these
devices are not required while installing the system.

</para><para arch="i386">

USB hardware generally works fine, only some
USB keyboards may require additional configuration 
(see <xref linkend="usb-keyboard-config"/>).

</para><para>

This section contains information about peripherals specifically
<emphasis>not</emphasis> supported by the installation system, even
though they may be supported by Linux.

</para><para arch="i386">

Again, see the 
<ulink url="&url-hardware-howto;">Linux Hardware Compatibility HOWTO</ulink>
to determine whether your specific hardware is supported by Linux.

</para><para arch="i386">

Note that the stock kernels do not support serial ports numbered
greater than four (<filename>/dev/ttyS3</filename>).  You'll have to
either use the available ports, or else build a custom kernel (see
<xref linkend="rescue-replace-kernel"/>).

</para><para arch="s390">

Package installations from XPRAM and tape are not supported by this
system.  All packages that you want to install need to be available on a
DASD or over the network using NFS, HTTP or FTP.

</para>
</sect1>

 <sect1 arch="not-s390"><title>Purchasing Hardware Specifically for GNU/Linux</title>

<para>

There are several vendors, who ship systems with Debian or other
distributions of GNU/Linux pre-installed.  You might pay more for the
privilege, but it does buy a level of peace of mind, since you can be
sure that the hardware is well-supported by GNU/Linux.  

</para><para arch="m68k"> 

Unfortunately, it's quite rare to find any vendor shipping
new &arch-title; machines at all. 

</para><para arch="i386"> 

If you do have to buy a machine with Windows bundled, carefully read
the software license that comes with Windows; you may be able to
reject the license and obtain a rebate from your vendor.  See 
<ulink url="&url-windows-refund;"></ulink> for complete details.

</para><para>

Whether or not you are purchasing a system with Linux bundled, or even
a used system, it is still important to check that your hardware is
supported by the Linux kernel.  Check if your hardware is listed in
the references found above.  Let your salesperson (if any) know that
you're shopping for a Linux system.  Support Linux-friendly hardware
vendors.

</para>

  <sect2><title>Avoid Proprietary or Closed Hardware</title>
<para>

Some hardware manufacturers simply won't tell us how to write drivers
for their hardware. Others won't allow us access to the documentation
without a non-disclosure agreement that would prevent us from
releasing the Linux source code.

</para><para arch="m68k"> 

Another example is the proprietary hardware in the older
Macintosh line. In fact, no specifications or documentation have ever
been released for any Macintosh hardware, most notably the ADB
controller (used by the mouse and keyboard), the floppy controller,
and all acceleration and CLUT manipulation of the video hardware
(though we do now support CLUT manipulation on nearly all internal
video chips).  In a nutshell, this explains why the Macintosh Linux
port lags behind other Linux ports.

</para><para>

Since we haven't been granted access to the documentation on these
devices, they simply won't work under Linux. You can help by asking
the manufacturers of such hardware to release the documentation. If
enough people ask, they will realize that the free software community
is an important market.

</para>
</sect2>


  <sect2 arch="i386"><title>Windows-specific Hardware</title>
<para>

A disturbing trend is the proliferation of Windows-specific modems and
printers. In some cases these are specially designed to be operated by
the Microsoft Windows operating system and bear the legend
``WinModem'' or ``Made especially for Windows-based computers''. This
is generally done by removing the embedded processors of the hardware
and shifting the work they do over to a Windows driver that is run by
your computer's main CPU. This strategy makes the hardware less
expensive, but the savings are often <emphasis>not</emphasis> passed on to the
user and this hardware may even be more expensive than equivalent
devices that retain their embedded intelligence.

</para><para>

You should avoid Windows-specific hardware for two reasons. The first
is that the manufacturers do not generally make the resources
available to write a Linux driver. Generally, the hardware and
software interface to the device is proprietary, and documentation is
not available without a non-disclosure agreement, if it is available
at all. This precludes its being used for free software, since free
software writers disclose the source code of their programs. The
second reason is that when devices like these have had their embedded
processors removed, the operating system must perform the work of the
embedded processors, often at <emphasis>real-time</emphasis> priority,
and thus the CPU is not available to run your programs while it is
driving these devices. Since the typical Windows user does not
multi-process as intensively as a Linux user, the manufacturers hope
that the Windows user simply won't notice the burden this hardware
places on their CPU.  However, any multi-processing operating system,
even Windows 2000 or XP, suffers from degraded performance when
peripheral manufacturers skimp on the embedded processing power of
their hardware.

</para><para>

You can help this situation by encouraging these manufacturers to
release the documentation and other resources necessary for us to
program their hardware, but the best strategy is simply to avoid this
sort of hardware until it is listed as working in the 
<ulink url="&url-hardware-howto;">Linux Hardware Compatibility HOWTO</ulink>.

</para>
</sect2>


  <sect2 id="Parity-RAM">
  <title>Fake or <quote>Virtual</quote> Parity RAM</title>
<para>

If you ask for Parity RAM in a computer store, you'll probably get
<emphasis>virtual parity</emphasis> memory modules instead of
<emphasis>true parity</emphasis> ones. Virtual parity SIMMs can often
(but not always) be distinguished because they only have one more chip
than an equivalent non-parity SIMM, and that one extra chip is smaller
than all the others. Virtual-parity SIMMs work exactly like non-parity
memory.  They can't tell you when you have a single-bit RAM error the
way true-parity SIMMs do in a motherboard that implements
parity. Don't ever pay more for a virtual-parity SIMM than a
non-parity one. Do expect to pay a little more for true-parity SIMMs,
because you are actually buying one extra bit of memory for every 8
bits.

</para><para>

If you want complete information on &arch-title; RAM issues, and what
is the best RAM to buy, see the 
<ulink url="&url-pc-hw-faq;">PC Hardware FAQ</ulink>.

</para><para arch="alpha"> 

Most, if not all, Alpha systems require true-parity RAM. 

</para>

  </sect2>

 </sect1>
1	<!-- retain these comments for translator revision tracking -->
2	<!-- $Id: supported-peripherals.xml 11568 2004-03-21 12:12:18Z waldi $ -->
3
4	<sect1 id="supported-peripherals">
5	<title>Peripherals and Other Hardware</title>
6	<para>
7
8	Linux supports a large variety of hardware devices such as mice,
9	printers, scanners, PCMCIA and USB devices. However, most of these
10	devices are not required while installing the system.
11
12	</para><para arch="i386">
13
14	USB hardware generally works fine, only some
15	USB keyboards may require additional configuration
16	(see <xref linkend="usb-keyboard-config"/>).
17
18	</para><para>
19
20	This section contains information about peripherals specifically
21	<emphasis>not</emphasis> supported by the installation system, even
22	though they may be supported by Linux.
23
24	</para><para arch="i386">
25
26	Again, see the
27	<ulink url="&url-hardware-howto;">Linux Hardware Compatibility HOWTO</ulink>
28	to determine whether your specific hardware is supported by Linux.
29
30	</para><para arch="i386">
31
32	Note that the stock kernels do not support serial ports numbered
33	greater than four (<filename>/dev/ttyS3</filename>). You'll have to
34	either use the available ports, or else build a custom kernel (see
35	<xref linkend="rescue-replace-kernel"/>).
36
37	</para><para arch="s390">
38
39	Package installations from XPRAM and tape are not supported by this
40	system. All packages that you want to install need to be available on a
41	DASD or over the network using NFS, HTTP or FTP.
42
43	</para>
44	</sect1>
45
46	<sect1 arch="not-s390"><title>Purchasing Hardware Specifically for GNU/Linux</title>
47
48	<para>
49
50	There are several vendors, who ship systems with Debian or other
51	distributions of GNU/Linux pre-installed. You might pay more for the
52	privilege, but it does buy a level of peace of mind, since you can be
53	sure that the hardware is well-supported by GNU/Linux.
54
55	</para><para arch="m68k">
56
57	Unfortunately, it's quite rare to find any vendor shipping
58	new &arch-title; machines at all.
59
60	</para><para arch="i386">
61
62	If you do have to buy a machine with Windows bundled, carefully read
63	the software license that comes with Windows; you may be able to
64	reject the license and obtain a rebate from your vendor. See
65	<ulink url="&url-windows-refund;"></ulink> for complete details.
66
67	</para><para>
68
69	Whether or not you are purchasing a system with Linux bundled, or even
70	a used system, it is still important to check that your hardware is
71	supported by the Linux kernel. Check if your hardware is listed in
72	the references found above. Let your salesperson (if any) know that
73	you're shopping for a Linux system. Support Linux-friendly hardware
74	vendors.
75
76	</para>
77
78	<sect2><title>Avoid Proprietary or Closed Hardware</title>
79	<para>
80
81	Some hardware manufacturers simply won't tell us how to write drivers
82	for their hardware. Others won't allow us access to the documentation
83	without a non-disclosure agreement that would prevent us from
84	releasing the Linux source code.
85
86	</para><para arch="m68k">
87
88	Another example is the proprietary hardware in the older
89	Macintosh line. In fact, no specifications or documentation have ever
90	been released for any Macintosh hardware, most notably the ADB
91	controller (used by the mouse and keyboard), the floppy controller,
92	and all acceleration and CLUT manipulation of the video hardware
93	(though we do now support CLUT manipulation on nearly all internal
94	video chips). In a nutshell, this explains why the Macintosh Linux
95	port lags behind other Linux ports.
96
97	</para><para>
98
99	Since we haven't been granted access to the documentation on these
100	devices, they simply won't work under Linux. You can help by asking
101	the manufacturers of such hardware to release the documentation. If
102	enough people ask, they will realize that the free software community
103	is an important market.
104
105	</para>
106	</sect2>
107
108
109	<sect2 arch="i386"><title>Windows-specific Hardware</title>
110	<para>
111
112	A disturbing trend is the proliferation of Windows-specific modems and
113	printers. In some cases these are specially designed to be operated by
114	the Microsoft Windows operating system and bear the legend
115	``WinModem'' or ``Made especially for Windows-based computers''. This
116	is generally done by removing the embedded processors of the hardware
117	and shifting the work they do over to a Windows driver that is run by
118	your computer's main CPU. This strategy makes the hardware less
119	expensive, but the savings are often <emphasis>not</emphasis> passed on to the
120	user and this hardware may even be more expensive than equivalent
121	devices that retain their embedded intelligence.
122
123	</para><para>
124
125	You should avoid Windows-specific hardware for two reasons. The first
126	is that the manufacturers do not generally make the resources
127	available to write a Linux driver. Generally, the hardware and
128	software interface to the device is proprietary, and documentation is
129	not available without a non-disclosure agreement, if it is available
130	at all. This precludes its being used for free software, since free
131	software writers disclose the source code of their programs. The
132	second reason is that when devices like these have had their embedded
133	processors removed, the operating system must perform the work of the
134	embedded processors, often at <emphasis>real-time</emphasis> priority,
135	and thus the CPU is not available to run your programs while it is
136	driving these devices. Since the typical Windows user does not
137	multi-process as intensively as a Linux user, the manufacturers hope
138	that the Windows user simply won't notice the burden this hardware
139	places on their CPU. However, any multi-processing operating system,
140	even Windows 2000 or XP, suffers from degraded performance when
141	peripheral manufacturers skimp on the embedded processing power of
142	their hardware.
143
144	</para><para>
145
146	You can help this situation by encouraging these manufacturers to
147	release the documentation and other resources necessary for us to
148	program their hardware, but the best strategy is simply to avoid this
149	sort of hardware until it is listed as working in the
150	<ulink url="&url-hardware-howto;">Linux Hardware Compatibility HOWTO</ulink>.
151
152	</para>
153	</sect2>
154
155
156	<sect2 id="Parity-RAM">
157	<title>Fake or <quote>Virtual</quote> Parity RAM</title>
158	<para>
159
160	If you ask for Parity RAM in a computer store, you'll probably get
161	<emphasis>virtual parity</emphasis> memory modules instead of
162	<emphasis>true parity</emphasis> ones. Virtual parity SIMMs can often
163	(but not always) be distinguished because they only have one more chip
164	than an equivalent non-parity SIMM, and that one extra chip is smaller
165	than all the others. Virtual-parity SIMMs work exactly like non-parity
166	memory. They can't tell you when you have a single-bit RAM error the
167	way true-parity SIMMs do in a motherboard that implements
168	parity. Don't ever pay more for a virtual-parity SIMM than a
169	non-parity one. Do expect to pay a little more for true-parity SIMMs,
170	because you are actually buying one extra bit of memory for every 8
171	bits.
172
173	</para><para>
174
175	If you want complete information on &arch-title; RAM issues, and what
176	is the best RAM to buy, see the
177	<ulink url="&url-pc-hw-faq;">PC Hardware FAQ</ulink>.
178
179	</para><para arch="alpha">
180
181	Most, if not all, Alpha systems require true-parity RAM.
182
183	</para>
184
185	</sect2>
186
187	</sect1>