## <a name="Known_Limitations_and_Fixes"> Known Limitations and Fixes </a>

When comparing the Hurd (and its [[Mach/GnuMach]] microkernel) to alternatives please remember that the last released version number is 0.3. For example, Linux, the kernel, took awhile to mature. The Debian GNU/Hurd system is developing rapidly. Assistance with programming and support tasks is greatly appreciated. The general [Hardware Compatibility Guide](http://www.freesoftware.fsf.org/thug/gnumach_hardware.html) is another good reference.

Now, the list of known limitations of the Hurd.

* ~1.5+ GB ext2 partition size limit
  * See [[ExtTwoSize]]

* Missing device drivers.
  * Current [[Mach/GnuMach]] drivers are from Linux 2.0.
  * [[Mach/OskitMach]] currently has Linux 2.2 drivers.

* Swap is [highly recommended](http://www.gnu.org/software/hurd/faq.en.html#q2-7), like on UNIX systems.

* Minimum of 8 MB RAM has been reported to work, but 32 MB is more realistic. Don't forget to use plenty of swap space.

* 768 megabytes RAM maximum [approximately](http://www.freesoftware.fsf.org/thug/gnumach_hardware.html#Memory). If you've got too much use GRUB's "uppermem" command to limit the amount seen by Mach.

* Random devices, /dev/random and /dev/urandom, are not in the main distribution yet. These are needed by, for instance, OpenSSH.
  * In progress, see [[RandomDevice]]

* No DHCP client will work yet.
  * See [[DhcpClient]] - need to update TCP/IP server.

* [[HurdConsole]] server not in CDs or tarballs yet.
  * Not true anymore [[Distrib/TarballNotes20030126]] provides.

* There are some [[Distrib/SystemAPILimits]]

* PthreadsLibrary not in CDs or tarballs yet.
  * May not be true anymore [[Distrib/TarballNotes20030126]] provides new Hurd libraries
  * See [[PosixThreads]]

* Sound support missing (in progress)
  * [[Mach/OskitMach]] will provide

* PPP support, e.g., um-pppd missing.
  * See [[PppDaemon]]

* USB support is missing

* XFree86 is stabilizing

* fatfs translator is stabilizing but it does not have partition limits that get in the way. ([0\.4 released Oct 6, 2002](http://mail.gnu.org/pipermail/bug-hurd/2002-October/010576.html))

* [Ext3 implementation](http://debian.fmi.uni-sofia.bg/~ogi/hurd/ext3fs/) has not started yet.

* Portability between alternate microkernels, e.g., [darwin](http://developer.apple.com/darwin/) &amp; [L4](http://os.inf.tu-dresden.de/L4/)