Linux is a clone of the Unix kernel, written from scratch by Linus Torvalds with assistance from a loosely-knit team of hackers across the Net. It aims towards POSIX and Single UNIX Specification compliance. It has all the features you would expect in a modern fully-fledged Unix kernel, including true multitasking, virtual memory, shared libraries, demand loading, shared copy-on-write executables, proper memory management, and TCP/IP networking.
Keepalived for LVS aims to add a strong and robust keepalive facility to the Linux Virtual Server project. This project is written in C with multilayer TCP/IP stack checks. It implements a framework based on three family checks: Layer3, Layer4, and Layer5. This framework gives the daemon the ability of checking a LVS server pool states.When one of the servers in the LVS server pool is down, keepalived informs the Linux kernel via a setsockopt call to remove this server entry from the LVS topology. In addition, it implements a VRRPv2 stack to handle director failover.
Kernel Mode Linux is a technology which enables the execution of user programs in a kernel mode. In Kernel Mode Linux, user programs can access kernel address space directly. Unlike kernel modules, user programs are executed as ordinary processes (except for their privilege level), so scheduling and paging are performed as usual. Although it seems dangerous, the safety of the kernel can be ensured through such methods as static type checking, software fault isolation, and so forth.
GeeXboX is a standalone media player Linux distribution, similar to MoviX. It's a small bootable CD that allows you to play your favorite video (DivX, XviD, H.264, MPEG 1/2, VCD, DVD, OggMedia, Windows Media, RealMedia, etc.) and audio (MP3, Audio CD, Ogg Vorbis, FLAC, MPC, etc.) files. It also supports networking, and is able to play media from Windows/Samba share, NFS, UPnP A/V Media Servers, RTP/RTSP servers, or SHOUTcast. It supports TV-out, TV tuners, DVB cards, and WiFi cards. It is based on MPlayer, and can be used on any x86, x86_64, or PowerPC computer. It's easy to modify the source to build your own GeeXboX or use an alternative boot method.
Visopsys is an alternative operating system for PC compatible computers. Under development since late 1997, this system is small, fast, and open source. It features a simple but functional graphical interface, real preemptive multitasking, and virtual memory. Though it attempts to be compatible in a number of ways, Visopsys is not a clone of any other operating system. You can demo the distribution from a "live" CD, USB stick, or floppy disk.
Linux NTFS provides Linux kernel drivers, a multiplatform NTFS library, and tools to create, resize, clone, rescue, query, label and fix NTFS volumes, and to undelete, resize, list, and query files for the filesystem used by Windows XP, 2003, 2000, NT4, and Vista. It also provides support for the Logical Disk Manager (LDM) that controls Windows' Dynamic Disks and is used to create software mirrors, stripes, and RAID.
ReactOS is an advanced operating system providing a ground-up implementation of a Microsoft Windows XP/Windows Server 2003-compatible operating system. It aims to achieve complete binary compatibility with both applications and device drivers meant for XP and NT 5.2 operating systems by using a similar architecture and providing a complete and equivalent public interface. Written completely from scratch, ReactOS is not a Linux based system, and shares none of the UNIX architecture.
L7-filter is a packet classifier for Netfilter that identifies packets based on application layer (OSI layer 7) data. This means that it is able to classify packets as HTTP, FTP, Gnucleus, Kazaa, etc., regardless of ports. It complements existing matches that classify based on port numbers, packet length, TOS bits, and so on. Combined with Linux QoS, it allows for full layer 7 packet shaping.
JBoss is an Open Source, standards-compliant, Enterprise JavaBeans application server implemented in pure Java. JBoss provides JBossServer, the basic EJB container and JMX infrastructure, JBossMQ for JMS messaging, JBossMail for mail, JBossTX for JTA/JTS transactions, JBossSX for JAAS based security, JBossCX for JCA connectivity, and JBossCMP for CMP persistence. It integrates with Tomcat Servlet/JSP container and Jetty Web server/servlet container, and enables you to mix and match these components through JMX by replacing any component you wish with a JMX-compliant implementation for the same APIs. The goal is to provide a full J2EE stack in the Free/Open Source software world.
ipt_pkd is an iptables extension implementing port knock detection with SPA (single packet authorization). This project provides 3 parts: the kernel module ipt_pkd, the iptables user space module libipt_pkd.so, and a user space client knock program. For the knock packet, it uses a UDP packet sent to a random port that contains a SHA-256 of a timestamp, small header, random bytes, and a shared key. ipt_pkd checks the time window of the packet and does the SHA-256 to verify the packet. The shared key is never sent.