{"history":[],"article":{"id":"982befba-ea70-47a8-8a4d-242d8798f529","title":"S3 (programming language)","slug":"s3-programming-language","content":":::summary\n**Name:** S3 \n**Paradigm:** [Structured](https://bliptext.com/articles/structured-programming), [imperative](https://bliptext.com/articles/imperative-programming) \n**Developer:** [International Computers Limited](https://bliptext.com/articles/international-computers-limited) \n**Influenced By:** [ALGOL 68](https://bliptext.com/articles/algol-68) \n:::\n\n# \n**S3** is a [structured](https://bliptext.com/articles/structured-programming), [imperative](https://bliptext.com/articles/imperative-programming) [high-level](https://bliptext.com/articles/high-level-language) [computer](https://bliptext.com/articles/computer-programming) [programming language](https://bliptext.com/articles/programming-language).\nIt was developed by the UK company [International Computers Limited](https://bliptext.com/articles/international-computers-limited) (ICL) for its [2900 Series](https://bliptext.com/articles/icl-2900-series) mainframes.\nIt is a [system programming language](https://bliptext.com/articles/system-programming-language) with syntax influenced by [ALGOL 68](https://bliptext.com/articles/algol-68) but with data types and operators aligned to those offered by the 2900 Series.\nIt was the implementation language of the [operating system](https://bliptext.com/articles/operating-system) [VME](https://bliptext.com/articles/icl-vme).\n\n# Annotated Example\nA rare example of an S3 program available in the public domain is the implementation of [Kermit](https://bliptext.com/articles/kermit-protocol) developed at the South-West Universities Regional Computer Centre, and archived in the [Columbia University](https://bliptext.com/articles/columbia-university) archive of [Kermit](https://bliptext.com/articles/kermit-protocol) implementations.\nThe examples below are selected highlights of the main module (kmt_main_module).\nThe program starts with a module identification, and comments which we quote by way of acknowledgment to the authors:\nMODULE KMT_MAIN_MODULE; @ Version 1.01 @\n@--@ @ @ @ @ @ - S W U R C C V M E K E R M I T - @\n@ @ @ @ @ @ @ @ @ @ @ Version 1.00 (February 1986) @\n@ @ @ Written by : Richard Andrews and David Lord, @\n@ South West Universities Regional Computer Centre, @\n@ Claverton Down, Bath BA2 7AY, U.K. @\n@ @ @ @ @ @ @ @ @ @ @ Version 1.01 (October 1986) @\n@ @ @ Fixes by : Dave Allum and David Lord, SWURCC.\n@ @ @\nNext follow a number of \"mode declarations\".\nMode is the Algol 68 term for a type.\nMODE KMT_BUFFER IS (96)BYTE;\nMODE KMT_STRING IS REFBYTE;\nMODE KMT_WORD IS REFBYTE;\nMODE KMT_MTM_VALUES IS ANY\n(LONG WORD LW_VALUE, LONG INT LI_VALUE, REF WORD RW_VALUE, REF INT RI_VALUE, REF LONG WORD RLW_VALUE, REF LONG INT RLI_VALUE, REFBYTE RVB_VALUE, REFREFBYTE RVRVB_VALUE);\nMODE KMT_PP_PACKET_STATISTICS_S IS STRUCT\n(INT INPUT_TOTAL, OUTPUT_TOTAL);\nThe first type is an array of 96 bytes; the next two are references (pointers) to arrays of bytes.\nKMT_MTM_VALUES is a union type allowing a variety of different types to appear.\nNote that WORD is a 32-bit unsigned integer, INT is a 32-bit signed integer; LONG makes it 64 bits.\nThe last option in the union is marked REFREFBYTE, which means it is a pointer to an array whose members are pointers to arrays of bytes.\nThe final type declared here is a STRUCT, specifically a tuple containing two integers.\nThe program continues by declaring external procedures on which the module depends.\nRESPONSE indicates a return value containing error information:\nEXT PROC (RESPONSE) KMT_UI;\nEXT PROC (REF INT,INT,RESPONSE) KMT_PH;\nEXT PROC (REF INT,REF INT,RESPONSE) KMT_PP_GET_PACKET,\nPROC (INT,INT,BOOL,RESPONSE) KMT_PP_SEND_PACKET,\nPROC (REFBYTE,RESPONSE) KMT_PP_BUILD_STRING_PACKET_DATA;\nand also some external variables:\nEXT REF BYTE KMT_VERSION;\nEXT REF BOOL ASG_ROUTE;\nEXT REFKMT_MTM_VALUES KMT_MTM_AREA;\nEXT REFBYTE MTM_TEXT;\nEXT REF INT MTM_TEXT_LEN;\nEXT REF REF BYTE MTM_RECALL_DATA;\nThe rest of the program consists of a number of procedure definitions.\nOne of these, which actually defines the entry point to the program, is reproduced here:\nGLOBAL STATIC () PROC KERMIT_THE_FROG IS (() REFBYTE OPTION, () REFBYTE VME_FILE, () REFBYTE REM_FILE, () RESPONSE RESULT):\nBEGIN\nBYTE JSV_NAME := \"ASG\"; @ obtain value for ASG_ROUTE bool @\nCTM_JS_READ(JSV_NAME,NIL,NIL,ASG_ROUTE,RC_IGNORED);\nIF RC_IGNORED NE 0 THEN ASG_ROUTE := FALSE FI;\n@ verify parameter references (parameter values validated later): @\n@ OPTION must be of mode REF BYTE, may not be ZLR or NIL @\n@ VME_FILE must be of mode REF BYTE, may be ZLR, must not be NIL @\n@ REM_FILE must be of mode REF BYTE, may be ZLR, must not be NIL @\nUNLESS (VERIFY OPTION AND VALIDR OPTION)\nAND (VERIFY VME_FILE AND (VALIDR VME_FILE OR NOT(VME_FILE IS NIL)))\nAND (VERIFY REM_FILE AND (VALIDR REM_FILE OR NOT(REM_FILE IS NIL)))\nTHEN @ invalid parameter reference @\nRESULT := 10002 @ ARCH_INACCESSIBLE_PARAMETER @\nELSF @ create resource block @\nCTM_JS_BEGIN(RESULT);\nRESULT <= 0\nTHEN @ resource block created @\nLONG LONG WORD KERMIT_RESULT;\nANY((3)LONG WORD AS_LW,(6) WORD AS_W) PARAMS;\nPARAMS.AS_LW := (BDESC OPTION,BDESC VME_FILE,BDESC REM_FILE);\n@ set up program error handler @\nIF KMT_EH_INFORM_PE_CONTINGENCY(RESULT);\nRESULT > 0\nTHEN @ failed to set error handler @\nSKIP\nELSF CTM_JS_CALL(NIL,PDESC KERMIT_SUPPORT,PARAMS.AS_W,KERMIT_RESULT, RESULT); @ create firewall @\nRESULT <= 0\nTHEN @ either exited normally or via CTM_STOP @\nRESULT := IF (S'S'KERMIT_RESULT) <= 0\nTHEN 0 @ ignore warnings @\nELSE 52000 @ error return common resultcode @\nFI FI;\nCTM_JS_END(RC_IGNORED) @ end resource block @\nFI END\nFeatures to note here include:","current_revision":null,"created_by":"kACnuQmH5k9Nr5VNVEpVeg7XpvUmMctD","created_at":"2025-01-26T09:38:21.625Z","updated_at":"2025-01-26T09:38:21.625Z","search_vector":"'languag':3 'program':2 's3':1","search_content":" \n**Name:** S3 \n**Paradigm:** [Structured](https://bliptext.com/articles/structured-programming), [imperative](https://bliptext.com/articles/imperative-programming) \n**Developer:** [International Computers Limited](https://bliptext.com/articles/international-computers-limited) \n**Influenced By:** [ALGOL 68](https://bliptext.com/articles/algol-68) \n \n\n# \n**S3** is a [structured](https://bliptext.com/articles/structured-programming), [imperative](https://bliptext.com/articles/imperative-programming) [high-level](https://bliptext.com/articles/high-level-language) [computer](https://bliptext.com/articles/computer-programming) [programming language](https://bliptext.com/articles/programming-language).\nIt was developed by the UK company [International Computers Limited](https://bliptext.com/articles/international-computers-limited) (ICL) for its [2900 Series](https://bliptext.com/articles/icl-2900-series) mainframes.\nIt is a [system programming language](https://bliptext.com/articles/system-programming-language) with syntax influenced by [ALGOL 68](https://bliptext.com/articles/algol-68) but with data types and operators aligned to those offered by the 2900 Series.\nIt was the implementation language of the [operating system](https://bliptext.com/articles/operating-system) [VME](https://bliptext.com/articles/icl-vme).\n\n# Annotated Example\nA rare example of an S3 program available in the public domain is the implementation of [Kermit](https://bliptext.com/articles/kermit-protocol) developed at the South-West Universities Regional Computer Centre, and archived in the [Columbia University](https://bliptext.com/articles/columbia-university) archive of [Kermit](https://bliptext.com/articles/kermit-protocol) implementations.\nThe examples below are selected highlights of the main module (kmt_main_module).\nThe program starts with a module identification, and comments which we quote by way of acknowledgment to the authors:\nMODULE KMT_MAIN_MODULE; @ Version 1.01 @\n@--@ @ @ @ @ @ - S W U R C C V M E K E R M I T - @\n@ @ @ @ @ @ @ @ @ @ @ Version 1.00 (February 1986) @\n@ @ @ Written by : Richard Andrews and David Lord, @\n@ South West Universities Regional Computer Centre, @\n@ Claverton Down, Bath BA2 7AY, U.K. @\n@ @ @ @ @ @ @ @ @ @ @ Version 1.01 (October 1986) @\n@ @ @ Fixes by : Dave Allum and David Lord, SWURCC.\n@ @ @\nNext follow a number of \"mode declarations\".\nMode is the Algol 68 term for a type.\nMODE KMT_BUFFER IS (96)BYTE;\nMODE KMT_STRING IS REFBYTE;\nMODE KMT_WORD IS REFBYTE;\nMODE KMT_MTM_VALUES IS ANY\n(LONG WORD LW_VALUE, LONG INT LI_VALUE, REF WORD RW_VALUE, REF INT RI_VALUE, REF LONG WORD RLW_VALUE, REF LONG INT RLI_VALUE, REFBYTE RVB_VALUE, REFREFBYTE RVRVB_VALUE);\nMODE KMT_PP_PACKET_STATISTICS_S IS STRUCT\n(INT INPUT_TOTAL, OUTPUT_TOTAL);\nThe first type is an array of 96 bytes; the next two are references (pointers) to arrays of bytes.\nKMT_MTM_VALUES is a union type allowing a variety of different types to appear.\nNote that WORD is a 32-bit unsigned integer, INT is a 32-bit signed integer; LONG makes it 64 bits.\nThe last option in the union is marked REFREFBYTE, which means it is a pointer to an array whose members are pointers to arrays of bytes.\nThe final type declared here is a STRUCT, specifically a tuple containing two integers.\nThe program continues by declaring external procedures on which the module depends.\nRESPONSE indicates a return value containing error information:\nEXT PROC (RESPONSE) KMT_UI;\nEXT PROC (REF INT,INT,RESPONSE) KMT_PH;\nEXT PROC (REF INT,REF INT,RESPONSE) KMT_PP_GET_PACKET,\nPROC (INT,INT,BOOL,RESPONSE) KMT_PP_SEND_PACKET,\nPROC (REFBYTE,RESPONSE) KMT_PP_BUILD_STRING_PACKET_DATA;\nand also some external variables:\nEXT REF BYTE KMT_VERSION;\nEXT REF BOOL ASG_ROUTE;\nEXT REFKMT_MTM_VALUES KMT_MTM_AREA;\nEXT REFBYTE MTM_TEXT;\nEXT REF INT MTM_TEXT_LEN;\nEXT REF REF BYTE MTM_RECALL_DATA;\nThe rest of the program consists of a number of procedure definitions.\nOne of these, which actually defines the entry point to the program, is reproduced here:\nGLOBAL STATIC ( ) PROC KERMIT_THE_FROG IS (( ) REFBYTE OPTION, ( ) REFBYTE VME_FILE, ( ) REFBYTE REM_FILE, ( ) RESPONSE RESULT):\nBEGIN\nBYTE JSV_NAME := \"ASG\"; @ obtain value for ASG_ROUTE bool @\nCTM_JS_READ(JSV_NAME,NIL,NIL,ASG_ROUTE,RC_IGNORED);\nIF RC_IGNORED NE 0 THEN ASG_ROUTE := FALSE FI;\n@ verify parameter references (parameter values validated later): @\n@ OPTION must be of mode REF BYTE, may not be ZLR or NIL @\n@ VME_FILE must be of mode REF BYTE, may be ZLR, must not be NIL @\n@ REM_FILE must be of mode REF BYTE, may be ZLR, must not be NIL @\nUNLESS (VERIFY OPTION AND VALIDR OPTION)\nAND (VERIFY VME_FILE AND (VALIDR VME_FILE OR NOT(VME_FILE IS NIL)))\nAND (VERIFY REM_FILE AND (VALIDR REM_FILE OR NOT(REM_FILE IS NIL)))\nTHEN @ invalid parameter reference @\nRESULT := 10002 @ ARCH_INACCESSIBLE_PARAMETER @\nELSF @ create resource block @\nCTM_JS_BEGIN(RESULT);\nRESULT 0\nTHEN @ failed to set error handler @\nSKIP\nELSF CTM_JS_CALL(NIL,PDESC KERMIT_SUPPORT,PARAMS.AS_W,KERMIT_RESULT, RESULT); @ create firewall @\nRESULT <= 0\nTHEN @ either exited normally or via CTM_STOP @\nRESULT := IF (S'S'KERMIT_RESULT) <= 0\nTHEN 0 @ ignore warnings @\nELSE 52000 @ error return common resultcode @\nFI FI;\nCTM_JS_END(RC_IGNORED) @ end resource block @\nFI END\nFeatures to note here include:","revisionCount":0},"hasMore":false,"nextCursor":null}

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