Projects - Ethan Brown

Project 01

Mortgage Amortization Calculator

COBOLJCLCGIShellz/OS

A full-stack mainframe integration project bridging modern web technologies with enterprise COBOL. A CGI shell script receives POST data from the web form, URL-decodes the loan parameters, and dynamically writes a complete JCL job that compiles and executes a COBOL batch program on z/OS. The script submits the job, polls the HFS output file for changes, and streams the resulting amortization schedule back to the browser as HTML all in a single request cycle.

CGI POST parsing and URL-decoding in pure shell
Runtime JCL generation - compiles and runs COBOL per request
Async job polling loop with HFS file change detection
End-to-end web - z/OS - browser pipeline

View Live ->

mortgage.cgi

# Decode POST body into loan parameters
POSTDATA=$(dd bs=1 count="$CONTENT_LENGTH" 2>/dev/null)

loan_title=$(urldecode \
    "$(echo "$POSTDATA" | sed -n \
    's/.*loan_title=\([^&]*\).*/\1/p')")
loan_total=$(urldecode \
    "$(echo "$POSTDATA" | sed -n \
    's/.*loan_total=\([^&]*\).*/\1/p')")
annual_rate=$(urldecode \
    "$(echo "$POSTDATA" | sed -n \
    's/.*annual_interest=\([^&]*\).*/\1/p')")

input_line="${loan_title},${loan_total},\
${annual_rate},${loan_years},${accel_pay},\
${payments_yr},${start_date},"

# Dynamically generate JCL - compile and run COBOL
cat > "$RUNJCL" <<EOF
//WEB524  JOB (ACCT),'WEB RUN',CLASS=A,MSGCLASS=X
//COBRUN  EXEC IGYWCL
//COBOL.SYSIN  DD DSN=S990085.COBOL.CBL(TESTFILE),DISP=SHR
//LKED.SYSLMOD DD DSN=S990085.COBOL.LOAD(TESTFILE),DISP=SHR
//RUN     EXEC PGM=TESTFILE,PARM='S990085'
//LOANFILE DD *
${input_line}
/*
//RESULT  DD DSN=S990085.COBOL.RESULT,DISP=OLD
EOF
submit "$RUNJCL"

# Poll HFS output file until job result lands
old_ts=$(stat -c %Y "$OUT_HFS" 2>/dev/null || echo 0)
WAITED=0
while [ $WAITED -lt $MAX_WAIT ]; do
    new_ts=$(stat -c %Y "$OUT_HFS" 2>/dev/null || echo 0)
    new_size=$(stat -c %s "$OUT_HFS" 2>/dev/null || echo 0)
    if [ "$new_ts" -gt "$old_ts" ] \
    || [ "$new_size" -gt "$old_size" ]; then
        break
    fi
    sleep $SLEEP
    WAITED=$((WAITED + SLEEP))
done

# Stream result back to browser
if [ -s "$OUT_HFS" ]; then
    cat "$OUT_HFS" | escape_html
else
    echo "No result yet. (Waited ${WAITED}s)"
fi

Project 02

SIC Assembler

CSystems ProgrammingAssemblySIC Architecture

A two-pass assembler for the Simplified Instructional Computer (SIC) architecture, written in C. Pass 1 tokenizes source lines, builds a symbol table with addresses, and validates directives and operands. Pass 2 resolves symbols, generates object code records (H, T, M, E) and writes a complete linkable object file. Supports ASCII and EBCDIC character encoding modes, indexed addressing via the ,X modifier, and all standard SIC directives including BYTE, WORD, RESB, RESW, START, and END.

Two-pass design: symbol table construction then object code generation
Full SIC directive support: BYTE, WORD, RESB, RESW, START, END
H/T/M/E record output compatible with SIC linking conventions
Indexed addressing, ASCII/EBCDIC modes, and robust error handling

main.c

/* Pass 1 - tokenize line, assign address, build symbol table */
token = strtok(line, search);
if (-1 != SymbolExists(MySymbolTable, token)) {
    printf("Duplicate Symbol Detected\n"
           "Terminating Project\n");
    fclose(fp);
    return -1;
}

if (isalpha((unsigned char)token[0])) {
    tempSymbol    = token;
    tempDirective = strtok(NULL, search);
    token         = strtok(NULL, search);

    if (!strcmp(tempDirective, "WORD")) {
        int val = strtol(token, NULL, 10);
        if (val >= 8388607 || val <= -8388608) {
            printf("Word exceeds 24-bit limit\n");
            fclose(fp); return -1;
        }
        MySymbolTable = InsertSymbol(
            MySymbolTable, tempSymbol,
            byteCount, fileLineCount + 1);
        byteCount += 3;
    }
    else if (!strcmp(tempDirective, "RESW")) {
        MySymbolTable = InsertSymbol(
            MySymbolTable, tempSymbol,
            byteCount, fileLineCount + 1);
        byteCount += strtol(token, NULL, 10) * 3;
    }
    else if (!strcmp(tempDirective, "RESB")) {
        MySymbolTable = InsertSymbol(
            MySymbolTable, tempSymbol,
            byteCount, fileLineCount + 1);
        byteCount += strtol(token, NULL, 10);
    }
    else {  /* standard instruction */
        MySymbolTable = InsertSymbol(
            MySymbolTable, tempSymbol,
            byteCount, fileLineCount + 1);
        byteCount += 3;
    }
}

/* Pass 2 - emit T records with resolved symbol addresses */
char *opCode = FindOpCode(records[i][1]);
int   address = SymbolExists(
    MySymbolTable, records[i][2]);

if (address == -1) {
    printf("Symbol Doesn't Exist\n"
           "Terminating Program\n");
    return -1;
}
sprintf(tRecords[tCount++],
    "T%06x%02x%s%04x\n",
    startCount, 3, opCode, address);
sprintf(mRecords[mCount++],
    "M%06x%02x+%s\n",
    startCount + 1, 4, records[0][0]);
startCount += 3;

Project 03

Work in Progress

Climate Risk Dashboard

PythonGeocodingFEMA DataData Pipeline

An end-to-end geospatial risk analytics platform currently in active development. The goal is to translate raw building addresses into composite hazard scores by geocoding to county-level FIPS codes and joining against FEMA National Risk Index datasets. Per-hazard scores across flood, wildfire, heat, and severe storm categories are normalized and combined into a weighted composite risk rating for display on an interactive dashboard.

Address geocoding to FIPS county codes via API
ETL pipeline joining user input to FEMA NRI datasets
Per-hazard risk scoring: flood, wildfire, heat, storms
Composite weighted risk score with interactive output

dashboard-preview.png