Year 1157 was a common year starting on Tuesday of the Julian calendar. January 12 – March 16 – Caliph Al-Muqtafi defends Baghdad against the coalition forces of Sultan Muhammad of Hamadan, Atabeg Qutb-adin of Mosul. Albert I of Brandenburg begins his ruthless program to pacify the Slavic region. June 11 – Albert I of Brandenburg called The Bear, becomes the founder of the Margraviate of Brandenburg and the first Margrave. August 21 – Sancho III and Ferdinand II, the sons of King Alfonso VII of Castile, divide his kingdom between them upon his death. October 23 – Battle of Grathe Heath: A civil war in Denmark ends with the death of King Sweyn III. Valdemar I of Denmark becomes king of all Denmark, restores and rebuilds the country. Henry II of England grants a charter to the merchants of Lincoln. Battle of Ewloe: Henry II of England invades Wales, is defeated by Owain Gwynedd. Nur ad-Din Zengi besieges the Knights Hospitaller in the crusader fortress of Banyas, routs a relief army led by King Baldwin III of Jerusalem, takes Grand Master Bertrand de Blanquefort prisoner.

September 8 – King Richard I of England Alexander Neckham, English scholar, teacher and abbot of Cirencester Abbey Leopold V of Austria, Duke of Austria from 1177 and Duke of Styria from 1192 until his death Margaret of France, Queen of England and Hungary, Queen of England by marriage to Henry the Young King and queen of Hungary and Croatia by marriage to Béla III of Hungary January 24 or January 25 – Agnes of Babenberg, Politically active High Duchess consort of Poland May 8 – Ahmed Sanjar, Great Seljuk Sultan May 15 – Yury Dolgoruky, Russian prince August 21 – King Alfonso VII of Castile October 23 – King Sweyn III of Denmark date unknown – King Eystein II of Norway 1157, a live album by Australian band Stars, released in 1980


Seccomp is a computer security facility in the Linux kernel. Seccomp allows a process to make a one-way transition into a "secure" state where it cannot make any system calls except exit, sigreturn and write to already-open file descriptors. Should it attempt any other system calls, the kernel will terminate the process with SIGKILL or SIGSYS. In this sense, it does not virtualize the system's resources but isolates the process from them entirely. Seccomp mode is enabled via the prctl system call using the PR_SET_SECCOMP argument, or via the seccomp system call. Seccomp mode used to be enabled by writing to a file, /proc/self/seccomp, but this method was removed in favor of prctl. In some kernel versions, seccomp disables the RDTSC x86 instruction, which returns the number of elapsed processor cycles since power-on, used for high-precision timing.seccomp-bpf is an extension to seccomp that allows filtering of system calls using a configurable policy implemented using Berkeley Packet Filter rules.

It is used by OpenSSH and vsftpd as well as the Google Chrome/Chromium web browsers on Chrome OS and Linux. Seccomp was first devised by Andrea Arcangeli in January 2005 for use in public grid computing and was intended as a means of safely running untrusted compute-bound programs, it was merged into the Linux kernel mainline in kernel version 2.6.12, released on March 8, 2005. Android uses a seccomp-bpf filter in the zygote since Android 8.0 Oreo. systemd's sandboxing options based on seccomp. QEMU, the Quick Emulator, the core component to the modern virtualization together with KVM uses seccomp on the parameter --sandbox Docker. Docker is a software. Docker can associate a seccomp profile with the container using the --security-opt parameter. Arcangeli's CPUShare was the only known user of seccomp for a while. Writing in February 2009, Linus Torvalds expresses doubt whether seccomp is used by anyone. However, a Google engineer replied that Google is exploring using seccomp for sandboxing its Chrome web browser.

Firejail is an open source Linux sandbox program that utilizes Linux Namespaces and other kernel-level security features to sandbox Linux and Wine applications. As of Chrome version 20, seccomp-bpf is used to sandbox Adobe Flash Player; as of Chrome version 23, seccomp-bpf is used to sandbox the renderers. Snap specify the shape of their application sandbox using'interfaces' which snapd translates to seccomp, AppArmor and other security constructs vsftpd uses seccomp-bpf sandboxing as of version 3.0.0. OpenSSH has supported seccomp-bpf since version 6.0. Mbox uses ptrace along with seccomp-bpf to create a secure sandbox with less overhead than ptrace alone. LXD, an Ubuntu "hypervisor" for containers Firefox and Firefox OS, which use seccomp-bpf Tor supports seccomp since Lepton, a JPEG compression tool developed by Dropbox uses seccomp Kafel is a configuration language, which converts readable policies into seccompb-bpf bytecode Subgraph OS uses seccomp-bpf Flatpak uses seccomp for process isolation Bubblewrap is a lightweight sandbox application developed from Flatpak minijail uses seccomp for process isolation Official website Google's Chromium sandbox,, August 2009, by Jake Edge seccomp-nurse, a sandboxing framework based on seccomp Documentation/prctl/seccomp_filter.txt, part of the Linux kernel documentation Security In-Depth for Linux Software: Preventing and Mitigating Security Bugs

1% rule (Internet culture)

In Internet culture, the 1% rule is a rule of thumb pertaining to participation in an internet community, stating that only 1% of the users of a website create new content, while the other 99% of the participants only lurk. Variants include the 1–9–90 rule, which states that in a collaborative website such as a wiki, 90% of the participants of a community only view content, 9% of the participants edit content, 1% of the participants create new content. Similar rules are known in information science, such as the 80/20 rule known as the Pareto principle, that 20 percent of a group will produce 80 percent of the activity, however the activity may be defined; the 1% rule states that the number of people who create content on the Internet represents 1% of the people who view that content. For example, for every person who posts on a forum about 99 other people view that forum but do not post; the term was coined by authors and bloggers Ben McConnell and Jackie Huba, although earlier references to the same concept did not use this name.

The terms lurk and lurking, in reference to online activity, are used to refer to online observation without engaging others in the community. A 2005 study of radical Jihadist forums found 87% of users had never posted on the forums, 13% had posted at least once, 5% had posted 50 or more times, only 1% had posted 500 or more times. A 2014 peer-reviewed paper entitled "The 1% Rule in Four Digital Health Social Networks: An Observational Study" empirically examined the 1% rule in health oriented online forums; the paper concluded that the 1% rule was consistent across the four support groups, with a handful of "Superusers" generating the vast majority of content. A study that year, from a separate group of researchers, replicated the 2014 van Mierlo study in an online forum for depression. Results indicated that the distribution frequency of the 1% rule fit followed Zipf's Law, a specific type of a power law; the "90–9–1" version of this rule states that for websites where users can both create and edit content, 1% of people create content, 9% edit or modify that content, 90% view the content without contributing.

The actual percentage is to vary depending upon the subject matter. For example, if a forum requires content submissions as a condition of entry, the percentage of people who participate will be higher than one percent, but the content producers will still be a minority of users; this is validated in a study conducted by Michael Wu, who uses economics techniques to analyze the participation inequality across hundreds of communities segmented by industry, audience type, community focus. The 1% rule is misunderstood to apply to the Internet in general, but it applies more to any given Internet community, it is for this reason that one can see evidence for the 1% principle on many websites, but aggregated together one can see a different distribution. This latter distribution is still unknown and to shift, but various researchers and pundits have speculated on how to characterize the sum total of participation. Research in late 2012 suggested that only 23% of the population could properly be classified as lurkers, while 17% of the population could be classified as intense contributors of content.

Several years prior, results were reported on a sample of students from Chicago where 60 percent of the sample created content in some form. A similar concept was introduced by Will Hill of AT&T Laboratories and cited by Jakob Nielsen; the term regained public attention in 2006 when it was used in a quantitative context within a blog entry on the topic of marketing. Digital citizen Netocracy Sturgeon's law Silent majority Participation Inequality: Lurkers vs. Contributors in Internet Communities by Jakob Nielsen, October 9, 2006. What is the 1% rule? by Charles Arthur in The Guardian, July 20, 2006. The 1% Rule by Heather Green in BusinessWeek, May 10, 2006 Institutions vs. Collaboration by Clay Shirky, July 2005, Video at 06:00 and 12:42