 | |
| Also known as | AS/400e, eServer iSeries, eServer i5, System i |
|---|---|
| Manufacturer | IBM |
| Type | Midrange computer |
| Release date | June 1988 (Announced) August 1988 (Release) |
| Discontinued | Sep 30, 2013 |
| Operating system | OS/400 (later known as i5/OS and IBM i) |
| CPU | |
| Predecessor | IBM System/38,IBM System/36 |
| Successor | IBM Power Systems runningIBM i |
| Related | IBM System p |
| Website | as400.ibm.com at theWayback Machine (archived 2000-03-02) |
TheIBM AS/400 (Application System/400) is a family ofmidrange computers fromIBM announced in June 1988 and released in August 1988. It was the successor to theSystem/36 andSystem/38 platforms, and ran theOS/400 operating system. Lower-cost but more powerful than its predecessors, an estimated 111,000 installations existed by the end of 1990 and annual revenue reaching $14 billion that year,[1] increasing to 250,000 systems by 1994,[2] and about 500,000 shipped by 1997.[3]
A key concept in the AS/400 platform isTechnology Independent Machine Interface[a] (TIMI), a platform-independentinstruction set architecture (ISA) that is translated to nativemachine language instructions. The platform has used this capability to change the underlying processor architecture without breaking application compatibility. Early systems were based on a 48-bitCISC instruction set architecture known as theInternal Microprogrammed Interface (IMPI), originally developed for the System/38.[4] In 1991, the company introduced a new version of the system running on a series of64-bitPowerPC-derived CPUs, theIBM RS64 family.[5] Due to the use of TIMI, applications for the original CISC-based programs continued to run on the new systems without modification, as the TIMI code can be re-translated to the new systems' PowerPCPower ISA native machine code. The RS64 was replaced withPOWER4 processors in 2001, which was followed byPOWER5 andPOWER6 in later upgrades.
The AS/400 went through multiple re-branding exercises, finally becoming theSystem i in 2006. In 2008, IBM consolidated the separate System i andSystem p product lines (which had mostly identical hardware by that point)[6] into a single product line namedIBM Power Systems.[7][8] The name "AS/400" is sometimes used informally to refer to theIBM i operating system running on modern Power Systems hardware.[9]
In the early 1980s, IBM management became concerned that IBM's large number of incompatiblemidrange computer systems was hurting the company's competitiveness, particularly againstDigital Equipment Corporation'sVAX.[10] In 1982, a project namedFort Knox commenced, which was intended to consolidate theSystem/36, theSystem/38, theIBM 8100, theSeries/1 and theIBM 4300 series into a single product line based around anIBM 801-based processor codenamedIliad, while retaining backwards compatibility with all the systems it was intended to replace.[11] A new operating system would be created for Fort Knox, but the operating systems of each platform which Fort Knox was intended to replace would also be ported to the Iliad processor to allow customers to migrate their software to the new platform.
The Fort Knox project proved to be overly ambitious and ran into multiple delays and changes of scope. As the project advanced, the requirement to support IBM 8100 and Series/1 software was dropped.[12] When IBM's engineers attempted to port the operating systems and software of their existing platforms, they discovered that it would be impossible without making extensive changes to the Iliad processor for each individual operating system — changes that Iliad's architects were unwilling to make.[11] The proposed solution to this was to augment Iliad with operating system-specific co-processors that provided hardware support for a single operating system. However, the amount of logic needed in each co-processor grew until the co-processors became the main processor, and the Iliad was relegated to the role of a support processor — thus failing the goal of consolidating on a single processor architecture. The Fort Knox project was ultimately cancelled in 1985.
During the Fort Knox project, askunkworks project was started atIBM Rochester by engineers who believed that Fort Knox's failure was inevitable. These engineers developed code that allowed System/36 applications to run on top of the System/38,[12] and when Fort Knox was cancelled, this skunkworks project evolved into an official project to replace both the System/36 and System/38 with a single new hardware platform.[13] The project became known asSilverlake (named forSilver Lake in Rochester, Minnesota) and officially began in December 1985.[14] The Silverlake hardware was essentially an evolution of the System/38 that reused some of the technology developed for the Fort Knox project.[12][15]
Silverlake's goal was to deliver a replacement for the System/36 and System/38 in as short a timeframe as possible, as the Fort Knox project had stalled new product development at Rochester, leaving IBM without a competitive midrange system.[16] On its launch in 1986, the System/370-compatibleIBM 9370 was positioned as IBM's preferred midrange platform, but failed to achieve the commercial success IBM hoped it would have.[11][17] Much like Silverlake, the 9370 also reused the co-processor developed during the Fort Knox project as its main processor and the same SPD I/O bus that was derived from theSeries/1 bus.[11]
On June 21, 1988, IBM officially announced the Silverlake system as theApplication System/400 (AS/400). The announcement included more than 1,000 software packages written for it by IBM and IBM Business Partners.[18] The AS/400 operating system was namedOperating System/400 (OS/400).[12]
The creators of the AS/400 originally planned to use the nameSystem/40, but IBM had adopted a new product nomenclature around the same time, which led to the Application System/400 name.[13] First, IBM began prefixing "System" in product names with words to indicate the intended use or target market of the system (e.g.,Personal System/2 andEnterprise System/9000). Second, IBM decided to reserve one- and two-digit model numbers for personal systems (e.g.,PS/2 andPS/55), three-digit numbers for midrange systems (e.g., AS/400) and four-digit numbers for mainframes (e.g.,ES/9000). The reassignment of two-digit model numbers from midrange systems to personal systems was to prevent the personal systems from running out of single-digit numbers for new products.
In 1990, IBM Rochester began work to replace the AS/400's original System/38-derived48-bitCISC processors with a 96-bit architecture known asC-RISC (CommercialRISC).[11] Rather than being a clean-slate design, C-RISC would have added RISC-style andVLIW-style instructions to the AS/400's processor, while maintaining backwards compatibility with theSystem/370-styleInternal Microprogrammed Interface (IMPI) instruction set and themicrocode used to implement it.
In 1991, at the request of IBM presidentJack Kuehler, a team under the leadership ofFrank Soltis delivered a proposal to adapt the64-bitPowerPC architecture to support the needs of the AS/400 platform.[19] Their extensions to the PowerPC architecture, known asAmazon (and later asPowerPC AS), were approved by IBM management instead of the C-RISC design for development into the next AS/400 processor architecture.[20] These extensions include support for tagged memory,[21] as well as assistance for decimal arithmetic.[22]
IBM initially attempted to create a single PowerPC implementation for both AS/400 and high-end RS/6000 systems known asBelatrix.[11] The Belatrix project proved to be too ambitious, and was cancelled when it became apparent that it would not deliver on schedule. Instead, a pair of AS/400-specific processors were designed at IBM Endicott and IBM Rochester, known asCobra (for low end systems) andMuskie (for high end systems) respectively. These became the initial implementations of theIBM RS64 processor line. The RS64 series continued to be developed as a separate product line at IBM until thePOWER4 merged both the RS64 and POWER product lines together.[13]
Despite the move from IMPI to an entirely different processor architecture, the AS/400'sTechnology Independent Machine Interface (TIMI) mostly hid the changes from users and applications, and transparently recompiled applications for the new processor architecture.[23] The port of OS/400 to the PowerPC AS architecture required a rewrite of most of the code below the TIMI due to the use of IMPI microcode to implement significant quantities of the operating system's low level code.[13] This led to the creation of the System Licensed Internal Code (SLIC) - a new implementation of the lower levels of the operating system mostly written inC++.
The AS/400 family line was rebranded several times in the 1990s and 2000s as IBM introduced newer generations of hardware and operating system.[23]
In 1994, theAS/400 Advanced Series name was used for new models, followed by the rebranding of the product line toAS/400e (thee standing fore-business) in 1997.[13]
In 2000, theeServer iSeries was introduced as part of itseServer branding initiative.[24] The eServer iSeries was built on thePOWER4 processor from the RS64 processors used by previous generations, meaning that the same processors were used in both the iSeries andpSeries platforms, the latter of which ranAIX.
In 2004,eServer i5 (along with OS/400 becomingi5/OS) the5 signifying the use ofPOWER5 processors, was introduced, replacing the eServer iSeries brand.[25] Successive generations of iSeries and pSeries hardware converged until they were essentially the same hardware sold under different names and with different operating systems.[6] Some i5 servers were still using the AS/400-specific IBM Machine Type (MT/M 9406-520) and were able to run AIX in an LPar along i5/OS, while the p5 servers were able to run i5/OS, respectively. The licensing for AIX and i5/OS was controlled in the firmware by the POWER hypervisor.
The final rebranding occurred in 2006, when IBM rebranded the eServer i5 toSystem i.[26]
In April 2008, IBM introduced theIBM Power Systems line, which was a convergence of System i and System p product lines.[7] The first Power Systems machines used thePOWER6 processors; i5/OS was renamed asIBM i in order to remove the association with POWER5 processors.[27] IBM i is sold as one of the operating system options for Power Systems (along with AIX and Linux) instead of being tied to its own hardware platform.
Although announced in 1988, the AS/400 remains IBM's most recent major architectural shift that was developed wholly internally[citation needed]. After the departure of CEOJohn Akers in 1993, when IBM looked likely to be split up,Bill Gates commented that the only part of IBM that Microsoft would be interested in was the AS/400 division. (At the time, many of Microsoft's business and financial systems ran on the AS/400 platform, rumored as ending around 1999 with the introduction ofWindows 2000.[28][29][30])
According toFrank Soltis, one of the architects of the AS/400 platform, the AS/400's architecture is defined by five architectural principles. Most of these principles are inherited from System/38.[31]
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The high-levelinstruction set (called TIMI for "Technology Independent Machine Interface" by IBM) allowsapplication programs to take advantage of advances in hardware and software without recompilation. TIMI is avirtual instruction set independent of the underlying machine instruction set of the CPU. User-mode programs contain both TIMI instructions and the machine instructions of the CPU, thus ensuring hardware independence. This is conceptually somewhat similar to thevirtual machine architecture of programming environments such asJava and.NET.
Unlike some other virtual-machine architectures in which the virtual instructions are interpreted atrun time, TIMI instructions are never interpreted. They constitute an intermediatecompile time step and aretranslated into the processor's instruction set as the final compilation step. The TIMI instructions are stored within the final program object, in addition to the executable machine instructions. This is how application objects compiled on one processor family (e.g., the originalCISC AS/400 48-bit processors) could be moved to a new processor (e.g.,PowerPC 64-bit) without re-compilation. An application saved from the older 48-bit platform can simply be restored onto the new 64-bit platform where the operating system discards the old machine instructions and re-translates the TIMI instructions into 64-bit instructions for the new processor.
The system's instruction set defines all pointers as 128-bit. This was the original design feature of theSystem/38 (S/38) in the mid-1970s planning for future use of faster processors, memory, and an expanded address space. The original AS/400 CISC models used the same 48-bit address space as the S/38. The address space was expanded in 1995 when theRISCPowerPCRS64 64-bit CPU processor replaced the 48-bit CISC processor.
OS/400 (now known as IBM i) is the native operating system of the AS/400 platform and was the sole operating system supported on the original AS/400 hardware. Many of the advanced features associated with the AS/400 are implemented in the operating system as opposed to the underlying hardware, which changed significantly throughout the life of the AS/400 platform. Features include aRDBMS (Db2 for i), a menu-driven interface, support for multiple users,block-oriented terminal support (IBM 5250), and printers.
Unlike the "everything is a file" principle ofUnix andits derivatives, on IBM i everything is an object (with built-in persistence and garbage collection).[citation needed]
IBM uses asingle-level store virtual memory architecture in the AS/400 platform. For 64-bit PowerPC processors, the virtual address resides in the rightmost 64 bits of a pointer while it was 48 bits in the S/38 and CISC AS/400. The 64-bit address space references main memory and disk as a single address set, which is the single-level store concept.
Later generations of hardware are also capable of supporting various guest operating systems, includingSSP,AIX,Linux,MicrosoftWindows 2000, andWindows Server 2003. While OS/400, AIX, and Linux are supported on the POWER processors onLPARs (logical partitions), Windows is supported with either single-processor internal blade servers (IXS) or externally linked multiple-processor servers (IXA and iSCSI). SSP guests were supported using emulation from OS/400 V3R6 through V4R4 using the Advanced 36 Machine facility of the operating system, a feature distinct from the System/36 Environment compatibility layer, which requires System/36 software to be recompiled.
| CPU | Year | Clock Speed | Server-Models | |
|---|---|---|---|---|
| IMPI[note 1] | 1988 | > 22 MHz[note 2] | Latest version:AS/400 | Bxx, Cxx, Dxx, Exx, Fxx, Pxx, 100, 135, 140, 2xx, 3xx[33] |
| Cobra (A10) | 1995 | 55 or 75 MHz | 4xx, 5xx | |
| Muskie (A25/A30) | 1996 | 125 or 154 MHz | 53x | |
| Apache (RS64) (A35) | 1997 | 125 MHz | 6xx, 150 | |
| NorthStar (RS64 II) | 1998 | 200, 255 or 262 MHz | 170, 250, 7xx, 650, S40, SB1[34] | |
| Pulsar (RS64 III) | 1999 | 450 MHz | Future version: iSeries;System i | 270, 820 |
| IStar (RS64 III upgraded) | 2000 | 400, 500, 540 or 600 MHz | 820, 830, 840,[35] SB2, SB3[36] | |
| SStar (RS64 IV) | 2000 | 540, 600 or 750 MHz | 270, 800, 810, 820, 830, 840 | |
| POWER4 | 2001 | 1.1 or 1.3 GHz | 890 | |
| POWER4+ | 2003 | 1.9 GHz | 825, 870 | |
| POWER5 | 2004 | 1.5 or 1.9 GHz | i5-520; i5-550; i5-570; i5-595 | |
| POWER5+ | 2005 | 1.5 GHz (2005) 1.9 GHz (2005) 2.2 GHz 2.3 GHz | i5-520, i5-550, i5-515, i5-525 i5-570 | |
| POWER6 | 2007 | 3.5 GHz 4.2 GHz 4.7 GHz | BladeCenter JS12, JS22 i5-570 (MMA) M50, M25 & M15 |
| Model | Year | CPU Group | Base -CPW |
|---|---|---|---|
| B10, B20, B30, B35, B40, B45, B50, B60, B70 | 1988-1989 | P10, P20 | 2,9 - 20 |
| C04, C06, C10, C20, C25 | 1990 | P10 | 3,1 - 6,1 |
| D02, D04, D06, D10, D20, D25, D35, D45, D50, D60, D70, D80 | 1991 | P10, P20, P30 | 3,8 - 56,6 |
| E02, E04, E06, E10, E20, E25, E35, E45, E50, E60, E70, E80, E90, E95 | 1992 | P10, P20, P30, P40 | 4,5 - 116,6 |
| F02, F04, F06, F10, F20, F25, F35, F45, F50, F60, F70, F80, F90, F95, F97 | 1993 | P05, P10, P20, P30, P40 | 5,5 - 177,4 |
| P01, P02, P03 | 1993-1995 | P05 | 7,3 - 16,8 |
| 150 | 1996 | P05 | 10,9 - 35,0 |
| S10, S20, S30, S40 | 1997 | P05, P10, P20, P30, P40, P50 | 45,4 - 4550 |
| SB1, SB2, SB3 | 1997-2000 | P30, P40 | 1794 - 16500 |
| 10S, 100, 135, 140 | 1993-1995 | P05, P10, P20 | 17,1 - 65,6 |
| 170 | 1998 | P05, P10, P20 | 30 - 1090 |
| 200, 20S, 236 | 1994 | P05, P10 | 7,3 - 17,1 |
| 250 | 2000 | P05 | 50 - 75 |
| 270 | 2000 | P05, P10, P20 | 50 - 2350 |
| 300, 30S, 310 | 1994 | P10, P20, P30, P40 | 11,6 - 177,4 |
| 400, 40S, 436 | 1995 | P05, P10 | 13,8 - 91,0 |
| 500, 50S, 510, 530, 53S | 1995 | P10, P20, P30, P40 | 18,7 - 650 |
| 600, 620, 640, 650 | 1997 | P05, P10, P20, P30, P40, P50 | 22,7 - 4550 |
| 720 | 1999 | P10, P20, P30 | 240 - 1600 |
| 730 | 1999 | P20, P30, P40 | 560 - 2890 |
| 740 | 1999 | P40, P50 | 3660 - 4550 |
| 800 | 2003 | P05, P10 | 300 - 950 |
| 810 | 2003 | P10, P20 | 750 - 2700 |
| 820 | 2000-2001 | P05, P10, P20, P30, P40 | 100 - 3700 |
| 825 | 2003 | P30 | 3600 - 6600 |
| 830 | 2000-2002 | P20, P30, P40, P50 | 1850 - 7350 |
| 840 | 2000-2002 | P40, P50 | 10000 - 20200 |
| 870 | 2002 | P40, P50 | 7700 - 20000 |
| 890 | 2002 | P50, P60 | 20000 - 37400 |
| 520 | 2004-2006 | P05, P10, P20 | 500 - 7100 |
| 550 | 2004-2006 | P20 | 3300 - 14000 |
| 570 | 2004-2006 | P30, P40 | 3300 - 58500 |
| 595 | 2004-2006 | P50, P60 | 24500 - 216000 |
| 515 | 2007 | P05 | 3800 - 7100 |
| 525 | 2007 | P10 | 3800 - 7100 |
| 570 | 2007 | P40 | 16700 - 58500 |
| MMA (9406) | 2007 | P30 | 5500 - 76900 |
| M15 | 2008 | P05 | 4300 |
| M25 | 2008 | P10 | 4300 - 8300 |
| M50 | 2008 | P20 | 4800 - 18000 |
| MMA | 2008 | P30 | 8150 - 76900 |
| JS12 | 2008 | P05 | 7100 |
| JS22 | 2008 | P10 | 13800 |
| JS23 | 2008 | ||
| JS43 | 2008 | ||
| 570 (9117) | 2008 | P30 | 104800 |
| 595 (9119) | 2008 | P60 | 294700 |
| Preceded by | IBM System p 2000 - 2008
| Succeeded by | |||||||||||
| Preceded by | IBM AS/400 1988 - 2008
| ||||||||||||
IBMmini/midrange computers, workstations, and servers | |||
|---|---|---|---|
| IBM 1130 | |||
| IBM 1400 | |||
| IBM System | |||
| AS/400 |
| ||
| RS/6000 |
| ||
| Other | |||
* Also based on the System/36 | |||
