i f d — h k oa t 4 x ae | te 4 a nie This is the fourth part of a series on IBM's -midrange com" puter famili, ! the AS/400. ... The AS/400 design incorpo- rates a number ii of advanced con- — cepts that con- — tribute to highly tl; T MARTIN machine interface, object-oriented de- : zs sign, single-level addressability, highly integrated system functions, an integrat- ed relational database and advanced en- — ment. These in- - elude a high-level a EPA gineering. These architectural features ] - tion in the cost of ownership of the sys- ' tem, particularly in support areas such ' |. tions traditionally performed by main: as basic instructions in the machine in: The high-level interface isolates appli: i ZMA u-a i ' -— AS/400's Des a poz z addressability makes main memory and . vice fails and the data on it cannot be "as a single, enormous pool of memory." ; /— All objects are accessed by name; pro-'! "the system, because a segment of nearly " grams and database objects are shared '/"' every object on the system may well , rather than having individual copies for'Y' have been resident on the damaged de- -,, each user, and all objects appear to be'!!":: vice. Very long recovery times are the > productive appli- "cation develop- effective- - | ly hide the complexity of the system 'F''" | from programmers, operators and users ' | through the use of a single system inter-'' | face. This results in a substantial reduc-. as systems programming, database sup- port, network management, operations : db ne! ' PI mejutii software, fit inte ee niji vratnega » The architecture of the AS/400 de- ? fines a logical machine instruction set at : a very high level, as illustrated in the!" figure. This high-level instruction set is ' called the machine interface. Many func-: frame operating systems are supported terface. For example, "Create Object" is : a single machine-interface instruction. " Cations developers from machine imple-. mentatlons. The approach accommo: '''" dates changes in the machine's underly-''. — PO WEEHNAPPLICATION DEVELOPMENT aj; ; a i 4 j K ii z ( ke ei mM da pora okras beE ii TS; vii s | DIA me a 4 EU > m s, 1. SA APPLIED INTELLIGENCE dro aii v o dobili čna SM (ivi nika vo dali sze, psov av šoli kič sa bar me tie li (za ; i ji On the AS/400, single-level s be v Za | Tax ni sd sk bi črke dolga > U: m iu: EL MU serious disadvantage. If one storage de- jmass storage appear to the programmer, %'' recovered, it may be necessary to reload all the data on all the storage devices on permanently resident in a single large ;'W ! inevitable result. memory. Single-level storage frees the '%'!3 IBM has sought to address this prob- . applications developer from disk- and %%" lem on the System/38 and AS/400 by |. memory-management constraints, and '//' improving the reliability of direct-access : allows an application to be independent: i/« storage devices, providing recovery-sup- ' of the configuration of the target 'X lj: li port aids such as journaling and platform. m ME eh REM checksum protection, and introducing Single-level addressability reguires a ''"'' specialized data-recovery utilities to its very large virtual-memory address to ac-"' technical-support personnel. Facilities to The AS/400's High-Level Machine Interface Instruction Set Off-Loads Funetions from the Operating System to the Hardware | EM ib. A function in a program running at this layer... Yfi Z, i k n ki SI ...IS translated here to a higher- level instruction set. Fewer oper- ations are re- uired to execute the function. | User- Interfaces zlalo Softw poča ii AS/400 Operating System are me [O uo 4 "mu ii JE Ji ble At this level, instructions are translated into microcode... High-Level Machine Interface yi (PRI laka Speajalu ai za je ni] H Hardware Ra PF] na DuLu Microprogramming Interface a .Which is then 4 si R , i i ui JUNE 5, 1989 Development and inconsistencies. Because each soft- ware component in conventional sys- tems is a self-contained entity, functions found in one component may be repeat: ' ed in others. In addition, highly trained support personnel with specialized skills " are needed to manage and control each specialized software component. '. The AS/400 was designed from the ground up to be an interactive, multi- user machine. Architectural features such as single-level addressability are particularly well-suited to an interac- <1 tive, multiuser environment. 'All application programs on the AS/400 are automatically compiled as re-entrant modules, so one physical copy of the code is shared by multiple users of the program. This provides efficient use of storage, and transaction-process- ing support is fully integrated with the operating-system software. No expensive specialists or laborious tricks of coding are reguired. Most significantly for us- ers, interactive processing on the AS/400 does not; "go down." The norm is S 100 percent, reliability. Ii: Integrated Relational Database ".. The AS/400 database-management system is based on the relational model, | and is integrated with both the operat- ing system and the machine. This pro- ' vides efficient performance for the in- formation system because operations are performed below the machine-inter- face level in a combination of microcode and hardware. Moreover, the in tegrity of the data is guaranteed because of the aa of security at the object evel. The database imp ports two kinds of files: physical and logical. A physical file is a data struc- ture consisting of rows (or records) and lementation sup- ing technology without any impact on '': Mental Ah Cotumns (or fields), each having č applications. ME tepaidikst Peron s machine. m | same field attribu ia gib zali: ng nč No Conversion Ne kre Functions of the High-level Machine Interface: lika jaka make views of oz krn, zA | 4 base and ma In effect, applications developed on Zi » Reduces the number of operations the machine must perform "namically. This flexibility NEKI in zmaj da of ppoaev will be ''' » Insulates the applications and operating system from the hardware combination with the performance and ee a vake advantage of new technolo- '' integrity of the AS/400, provides stran ges without reguiring conversion. ni si; .. id Y šu Sri klpojetiin sfajs s rrnike peti PEPE ia dos | Support for user a ee ta ne AS/400 is an object.oriented sys- ': is) (ala id ME ke a ee SO ZA. šmkeken — systems and contributes to m AJA | tem. Programs, data files, gueues TKA o nel! NEU Oz lk SE Xi stov ao go z deka Ge ibutea to a reduction uz LU | dibi - IV POT MKL za zijilal NE i ; V h — | KE | ka una: cy. les, device deseriptions, user profiles— EN — The AS/400 hardware i by ai lato ve koč njo TEVA Was designed from the ground up to be an inter. ber of sophisticated engineering fea. cess to objesta is by object name rather '- 2CUVve, multiuser machine. Architecturc Jeatures such as computer stena TIČ ARN oceni je obla on A key characteris. | singlelevel addressability are uelLsui ži in hlehrend AS/4O) nap poe | tic of objectoriented svste.. če polit: nglelevel € MAROKO nility are well-suited to that environment. BNs tn s a) models incorporates ee Systems. The ob- s aii še sk kA: bič io RA sal Sem ste dasi HER IBM s fastest bipolar chip technol Ee design of the AS/400 frees "'/:' //' [ oo bt sa lčrrz Ji ERA —— lg side, —- with a cycle time of 60 nanoseconde, | tions programimne from low- Mi eh HA CI i, iii 7A t [i ta: Y i, si tili J: SEG LEdi seme te obe če and megabit Mer V nisem level concerns with information retriev- "|" co; al t | bil | ; The AS/40 o enlp« al and storage. It also provides a uni- " A obče m pe ile TISANJA od js malntain mirror-image copies of files on. OEEO NES usedi: O EMA lorm interface to all objects, a high de- '' support Ge ane.