HPUnix

The operating system controls how system resources are distributed. HP-UX is both multiuser and multitasking. This means that you can have a small number of users, or if you have an HP-UX corporate business server, as many as thousands of users who must use system resources in order to do their work. The result may be many processes that need to be executed simultaneously in order for people to get their jobs done. HP-UX manages what processes will get what system resources at what time and for what time interval. Files System & Types There are four file system types supported by HP-UX: � High Performance File System (HFS) is HP's version of the UNIX File System. This is the most common file system and the one used in most of the examples. � CD-ROM File System (CDFS) is used when you mount a CD-ROM. A CD-ROM is read-only, so you can't write to it. � Network File System (NFS) is a way of accessing files on other systems on the network from your local system. An NFS mounted file system looks as though it is local to your system even though it is located on another system. � Loopback File System (LOFS) allows you to have the same file system in multiple places. � VxFs? is an extent-based Journal File System that supports fast file system recovery and online features, such as backup. HP-UX File Types [1]

Files and directories are organized by category. The operating system and applications are kept separate from one another Intrasystem files are kept in a separate area from intersystem, or network-accessible, files. /usr and /sbin are shared operating system directories. Executable files are kept separate from system configuration files so that the executables may be shared among hosts. Every file on the system has a file name. The operating system takes care of all file-system-related tasks; you just need to know the name of the file and how to use it. The following are file types: � text files � data files � source code files � executable files � shell programs � links � device files

Security HP-UX is both multi-user and multi-tasking and for log on Names and Password, HP-UX cares a great deal about uppercase and lowercase.

Graphical User Interfaces User environments are bundled with HP-UX. The HP Visual User Environment (HP VUE) and Common Desktop Environment (CDE) are bundled with HP-UX systems.

Scalability There is, however, no typical HP-UX installation. One of the big advantages of open systems is flexibility, and one of the particularly big advantages of the HP-UX product line is that it is highly scalable. This means that you may end up with one or more larger systems shared among users or a highly distributed environment in which each person has his own workstation

Networking A highly distributed environment also takes advantage of the bundled networking and user environments that come with HP-UX. The networking allows systems to communicate on an ongoing basis and to provide such functionality as allowing your files to be stored anywhere on the network, like the server, with complete transparency to you. [3] mobile IP support Resilience HP-UX supports HP's Instant Capacity on Demand (iCOD), which allows additional processors to be brought online nearly instantaneously when the system load requires it. Disaster Tolerance - By using HP Campus Cluster disaster tolerant solutions, you can now place systems and storage in different buildings to achieve higher levels of availability. To provide architectural flexibility, Campus Cluster solutions are based on either Fibre Channel or Symmetrix Remote Data Facility (SRDF) technology. [2] Web Support With HP's Web serving products, Internet and intranet web sites operate in high performance and reliability with complete end-to-end Secure Socket Layer (SSL). With these capabilities, you can deliver dynamic content to the web site or keep your secured e-Commerce store always open for e-Business. With HP's Web serving products, Internet and intranet web sites operate in high performance and reliability with complete end-to-end Secure Socket Layer (SSL). With these capabilities, you can deliver dynamic content to the web site or keep your secured e-Commerce store always open for e-Business. In addition, HP-UX 11i supports a wide range of intranet and Internet networking links, protocols and higher level networking services so you can connect any device, any place, any time

The following Web Servers and internet services are supported: hp Apache-based web server and zeus web server internet services - The newest versions of BIND, DHCPv6?, WU-FTP, Sendmail, TCP Wrappers and SLP are available for free download at software depot

[1]http://www.interex.org/pubcontent/interact/apr96/6ponia/ponia.html [2]http://www.hp.com/products1/unix/highavailability/dpdt/096/infolibrary/dis_tol_sol_campus.html [3]http://www.interex.org/pubcontent/interact/jan96/09ponia/ponia.html

FEATURES HP-UX 2000 ADVANCED SERVER RED HAT LINUX COMMENTS File System Support HFS Yes NFS Yes CDFS Yes (HP Read Only) LOFS Yes JFS Yes I/O File Types Supported text files, data files, source code files, executable files, shell programs, links, device files. Multi-user Yes Multi-Tasking Yes Instant Capacity on Demand Yes Security Upper & Lower Case used for log on & Passwords Disaster Tolerance Support Yes � Fibre Channel or SRDF

Network Systems Distributed Yes (HP Highly) Centralised Yes (HP Highly) GUI HP VUE & CDE Web Servers Supported HP Apache, Zeus Internet Services BIND, DHCPv6?, WU FTP, Sendmail, TCP Wrappers SLP Scalable Yes (HP Highly)

HP Unix

HP-UX is now at revision 11i and is a UNIX operating system that is used on both HP�s own PA-RISC and Intel�s Itanium processor families. In addition to a 64-bit version of HP-UX 11, the company continues to offer support for a 32-bit version.The operating system is used for batch processing, decision support, electronic commerce, file serving, Internet and intranet access and enterprisewide activities, online transaction processing, and technical computer-intensive applications. HP-UX is a higher-end Unix operating system and it is geared toward the server and power workstation user. HP-UX 11i is moving toward current development trends, where developers build applications on Windows and Linux and then deploy them on HP-UX; this new version simplifies the transition of Windows and Linux applications to HP-UX "[#1]":#ref1 Supports mutliprocessors and up to 256 GB memory.

Processes & Threads

Thread Support

The CMA threads (libcma) package, which is POSIX P1003.1a (Draft 4) compliant, is based on Concert Multi Thread Architecture (CMA). CMA is a user-level threads package in which thread scheduling and synchronization are handled within the user space without the kernel's assistance.

CMA threads have been deprecated (slated for future obsolescence) at HP-UX 11i. This development environment will not be shipped in a future HP-UX release. Also, there is no plan to release native IPF CMA threads on IPF platforms. Therefore, HP now strongly recommends that you use the currently supported kernel threads libraries and development tools. Thus, applications using CMA threads should start migrating to kernel threads.

Multi-threading is also supported in the HP-UX kernel at 11i and is known as kernel, POSIX or 1x1 threads. The kernel threads implementation allows the application to take advantage of multiple processors in the system to parallelize execution of threads "[#4]":#ref4.

The System-V IPC kernel tunable MSGMNB, which sets the maximum number of bytes on a queue, has had its maximum upper limit increased from 64KB to 64MB "[#5]":#ref5

Memory Management "[#2]":#ref2

The memory management system is designed to make memory resources available safely and efficiently to threads and processes. Minimally, there will be the following resources consuming memory:

        HP-UX Operating System  10 -12 MB
        Windowing System        21 MB (X11)   25 MB (VUE)   32 MB (CDE)

HP-UX uses paging to move pages in and out of physical memory. The operating system and any pages that have been explicitly (or implicitly) locked are not subject to paging. Only the pages of a process that are required for execution will be paged in. Text (instructions) pages are never "paged out".

HP-UX memory management is composed of 3 basic elements: cache, memory and swap space. Swap space can be composed of two types: device swap and file system swap. Device swap can be made up of primary swap space that is defined on the root disk and secondary swap space which is defined on other disk volumes. All of these elements can be configured/optimized through HP-UX kernel parameter tuning. "[#7]":#ref7

Physical Memory Support

The system uses a combination of pageout and deactivation to manage physical memory.

The page size of all HP-UX systems is four kilobytes. Lockable Memory Pages kept in memory for the lifetime of a process by means of a system call improve application performance.

Virtual Memory Support

A computer has a finite amount of RAM available, but each 32-bit HP-UX process has a 4 GB virtual address space apportioned in four one-gigabyte quadrants. (64-bit HP-UX processes have an even larger virtual address space, though they can't actually use the full (16 Exabyte) range of virtual addresses addressable with 64 bits. It too is broken into 4 quadrants equal sized quadrants.) This is termed virtual memory.

Virtual Addresses

The offset may be 32 bits or 64 bits wide.

Demand Paging

Pages are not loaded in memory until they are "demanded" by a process.

Organization and Types of TLB

Depending on model, the TLB may be organized on the processor in one of two ways:

Unified TLB: A single TLB that holds translations for both data and instructions.
Split Data and Instruction TLB: Dual TLB units in the processor each of which hold translations specifically for data or instructions.

The advantage of having a split Data TLB (DTLB) and Instruction TLB (ITLB), is that it is possible to account for the different characteristics of data and instruction locality and type of access (frequent random access of data versus relatively sequential single usage of instructions).

Cache Organization: Depending on model, PA-RISC processors are equipped with either a unified cache or separate caches for instructions and data (for better locality and faster performance). In multiprocessing systems, each processor has its own cache, and a cache controller maintains consistency.

The OS Kernel may be optimised by the use of kernel variables that allow the operating system to be configured to fit specific system needs, resulting in better performance and/or more efficient allocation of resources "[#3]":#ref3.

Memory Windows

Running without memory windows, HP-UX has limitations for shared resources on 32-bit applications. All applications in the system are limited to a total of 1.75GB of shared memory (2.75GB if compiled as SHMEM_MAGIC). In a system with 16GB of physical memory, only 1.75 can be used for shared resources. To address this limitation, a functional change has been made to allow 32-bit processes to create unique memory windows for shared objects like shared memory. The memory window for default executables is 1GB. This allows cooperating applications to create 1GB of shared resources without exhausting the system-wide resource. Part of the virtual address space remains globally visible to all processes, so that shared libraries are accessible no matter what memory window they are in "[#6]":#ref6.

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