DEPOSIT/i — Core Banking / Demand Deposit

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DEPOSIT/i is an AS/400-native core banking / demand-deposit (DDA) system: customer and account masters, teller postings (deposit / withdrawal / transfer) against a running-balance ledger, holds that reduce available balance, tiered daily interest accrual with month-end crediting, service charges plus dormancy flagging, overdraft-limited withdrawals, a balanced double-entry general-ledger feed, and passbook/trial-balance print. It is a classic RPG IV + ILE COBOL + DDS + embedded-SQL application: the business math lives in packed-decimal RPG that reads and updates keyed physical files and appends to a journaled ledger, while the GL feed and its cross-checks run through EXEC SQL against a DB2 table. This manual is the reference for the operator who runs the teller line, the online inquiry screens and the nightly batch chain, and for the developer maintaining the application. It is grounded entirely in the committed source (banking-app/src/sources.mjs, src/seed.mjs, and the test/dep_*.mjs drivers).

A. Overview & Architecture ↑ top

A.1 What it does

DEPOSIT/i runs a single line of business — retail demand-deposit banking (savings + checking):

• Account maintenance — open new accounts, change status (active / dormant / closed), and re-rate an account's interest rate, driven from a pending work file (ACCTMNP → ACCTMNT).
• Teller postings — deposits, withdrawals (limited by available balance + overdraft), and transfers (a two-leg debit + credit), posted from a pending work file (TXNPEND → TELLER), each appending a running-balance row to the journaled ledger TXNJRNL.
• Holds — open holds on an account reduce its available balance; HOLDPOST recomputes AVLBAL = CURBAL − Σ(open holds).
• Interest — INTACCR accrues one day of tiered simple interest into the ACCRINT bucket per active account; INTCRED credits the accrued interest into the balance at month-end and posts an interest ledger row.
• Service charges & dormancy — SVCCHG posts a monthly maintenance fee (unless the minimum-balance waiver applies) and flags stale accounts dormant.
• GL feed & reporting — GLPOST consolidates the day's ledger activity into balanced DR/CR rows in the DB2 GLLEDGER table; TRIALRPT and the COBOL DDABAL prove and cross-check DR=CR; STMTGEN prints a passbook / statement register.

A.2 A single RPG/COBOL layer over keyed files + a DB2 GL feed

Unlike a stored-procedure design, DEPOSIT/i keeps all business logic in the application programs themselves. There are two data substrates with a clear division of use:

• Native record I/O (the operational store). Masters, the ledger and the work files are keyed DDS physical files. The RPG programs CHAIN/READ/SETLL them, do packed-decimal money math in-line, and UPDATE/WRITE the result. The ledger TXNJRNL is journaled (STRJRNPF) so every posting captures a before/after image.
• Embedded SQL over DB2 (the GL feed + cross-checks). The general ledger is a DB2 table GLLEDGER. GLPOST inserts balanced DR/CR rows through EXEC SQL INSERT and cross-checks the batch with an aggregate query; TRIALRPT reads it with an SQL cursor; the COBOL DDABAL totals the account master via a COMP-3 FD and cross-checks it against an SQL SUM over the ledger. The next ledger transaction id is also read with an EXEC SQL SELECT MAX(TXNID).

The consequence for operations: money movement is native-file and immediate (and journaled for audit), while the general ledger — the place a balanced control total is proven — is SQL, and is the only substrate under commitment control (see F.3). Everything runs in library DEPOSIT.

A.3 Component & flow

  MAINTENANCE           ONLINE (5250)          BATCH (night chain / on demand)
  -----------           -------------          ------------------------------
  ACCTMNP --READ-->     TELMENUP (menu)        INTACCR  --> ACCTMST.ACCRINT (tiered daily)
    ACCTMNT               opt 1 -> ACCTINQ     INTCRED  --> ACCRINT into CURBAL + 'I' TXN
    (O/C/R)              (plain inquiry)        SVCCHG   --> 'C' fee TXN + dormant flag
                         opt 2 -> REGINQ        GLPOST   --> GLLEDGER DR/CR (SQL, balanced)
  TXNPEND --READ-->     (SFL register)          TRIALRPT --> TRIALPR trial balance (DR=CR)
    TELLER                                       STMTGEN  --> STMTPR passbook/statement
    (D/W/X)                                      DDABAL   --> COBOL COMP-3 total vs GL SUM
       |     \                                  /
       |      \                                /
       v       v                              v
   ACCTMST  <--update-- HOLDPOST (AVLBAL = CURBAL - open holds)
       |
       +--> TXNJRNL (append-only, journaled to TXNJRN; running balance per row)
                |
                +--> TXNLF (keyed by account) --> REGINQ subfile + STMTGEN register

A single teller posting flows: an op is written to TXNPEND → TELLER reads it, CHAINs ACCTMST, validates available balance (+ overdraft), updates CURBAL/AVLBAL, and WRITEs a TXNJRNL row carrying the running balance → the journal captures the ledger WRITE. A transfer is two such postings (a TRANSFER OUT debit leg and a TRANSFER IN credit leg).

A.4 Object inventory

Object	Type	Role
CUSTMST	PF	Customer master.
ACCTMST	PF	Account master (the heart of the app).
TXNJRNL	PF (journaled)	Teller transaction ledger (append-only).
TXNLF	LF	Ledger keyed by account then txn id (register/passbook).
HOLDMST	PF	Holds against available balance.
HOLDLF	LF	Holds keyed by account.
INTPLAN	PF	Interest rate tiers (product + balance band).
CHGPLAN	PF	Service-charge plans.
TXNPEND	PF	Pending teller-op work file.
ACCTMNP	PF	Pending account-maintenance work file.
GLLEDGER	DB2 table	Double-entry GL feed (SQL DDL).
ACCTDSPF / REGDSPF / TELMENU	DSPF	Inquiry / subfile register / menu displays.
STMTPR / TRIALPR	PRTF	Statement/passbook & trial-balance printer files.
SEEDDATA	RPGLE	Data-seed loader (customers/accounts/tiers/plans/hold).
ACCTMNT	RPGLE	Account master maintenance (open/change/re-rate).
HOLDPOST	RPGLE	Recompute available balance from open holds.
TELLER	RPGLE + SQL	Post deposits/withdrawals/transfers.
INTACCR	RPGLE	Daily tiered interest accrual (packed-decimal).
INTCRED	RPGLE + SQL	Month-end interest crediting.
SVCCHG	RPGLE + SQL	Service charges + dormancy flagging.
GLPOST	RPGLE + SQL	Balanced DR/CR GL feed + control total.
STMTGEN	RPGLE	Passbook/statement PRTF register.
TRIALRPT	RPGLE + SQL	GL trial-balance PRTF (DR=CR).
ACCTINQ	RPGLE	Plain WORKSTN account inquiry.
REGINQ	RPGLE	SFL/SFLCTL account-register subfile.
TELMENUP	RPGLE	Menu program routing to the two inquiries.
DDABAL	ILE COBOL + SQL	COMP-3 ledger total vs GL SUM cross-check.
DBSETUP / DBNIGHT	CL	Build-everything driver / night-batch chain.

The catalogue is 8 PFs + 2 LFs + 1 DB2 table, 3 DSPFs + 2 PRTFs, driven by 13 RPG programs + 1 ILE COBOL program + 2 CL drivers. Sections D and F expand each.

B. Online Transactions & Screens ↑ top

B.1 The command/entry line

DEPOSIT/i has no CICS transaction identifiers and no transid switch. On IBM i, each program is reached by name from a 5250 command-entry line (or a JOBQ/scheduler for the batch jobs). The operator equivalent of "type a transid and Enter" is "type a CALL command and Enter". Before invoking anything, the job's library list must include DEPOSIT — the tested jobs run with LIBL = QSYS QGPL DEPOSIT QTEMP and CURLIB = DEPOSIT.

To do this	Type on the command line
Open the teller menu (routes to the two inquiries)	CALL DEPOSIT/TELMENUP
Open the plain account inquiry directly	CALL DEPOSIT/ACCTINQ
Open the account register (subfile) directly	CALL DEPOSIT/REGINQ
Apply pending account maintenance	CALL DEPOSIT/ACCTMNT
Post the pending teller ops	CALL DEPOSIT/TELLER (or SBMJOB it)
Recompute available balances from holds	CALL DEPOSIT/HOLDPOST
Build/rebuild the whole app + seed	CALL DEPOSIT/DBSETUP
Submit the night batch chain	CALL DEPOSIT/DBNIGHT

The maintenance/teller/batch programs take no CALL parameters — each reads its work from a pending file (ACCTMNP, TXNPEND) or processes every account, and DSPLYs a one-line result. There is no interactive posting screen: postings and maintenance are driven from the pending work files (the classic AS/400 work-file → poster idiom), and the interactive programs (TELMENUP, ACCTINQ, REGINQ) are inquiry only.

B.2 The menu & inquiry screens (TELMENUP / ACCTINQ / REGINQ)

Three WORKSTN programs make up the online tier. TELMENUP displays a two-option menu (TELMENU / record MENUFMT) and dynamically CALLs ACCTINQ for option 1 or REGINQ for option 2. Both inquiry programs loop on EXFMT until F3 (CA03), and both look an account up by CHAINing ACCTMST then CUSTMST for the customer name.

The teller menu (TELMENUP / TELMENU)

Option 1 sets indicator 81 and calls ACCTINQ; option 2 sets 82 and calls REGINQ; anything else shows Invalid option. (The fixed-form CALLs are indicator-conditioned in cols 9–11 — see quirk PQ-1.)

Plain account inquiry (ACCTINQ / ACCTDSPF)

A single, non-subfile display (ACCTINQ record ACCTINQF). The operator keys an account number in IACCTNO; on Enter the program chains the master and shows the customer name, product (SAVINGS / CHECKING from PRODCD), status (ACTIVE / DORMANT / CLOSED from ASTAT), and the current / available / accrued figures. An unknown account yields Account not found: nnnnnnnnnn.

Account register subfile (REGINQ / REGDSPF)

REGINQ is the app's one subfile screen (DDS record REGSFL under control record REGCTL, SFLPAG(0012) per page, SFLSIZ(0030)). The operator keys an account in IREACCT; the program clears the subfile (SFLCLR, indicator 33), then loops the ledger logical TXNLF keyed by that account (SETLL / READE), WRITEing one REGSFL row per transaction, and EXFMTs the register — a real "clear, load, display" subfile pass, reloaded each time an account is inquired.

Subfile columns (REGSFL)

Field	Type (DDS)	Shows
SXDT	8A output	Transaction date (from TXNDT).
SXTYP	1A output	Type: D deposit, W withdrawal, X transfer, I interest, C charge.
SXAMT	14A output	Transaction amount (from TXNAMT).
SXBAL	14A output	Running balance after this posting (from RUNBAL).
SXDESC	20A output	Posting description (from DESCR).

B.3 Controls & audit workflow (no four-eyes maker–checker)

Honest statement: DEPOSIT/i does not model a true four-eyes maker–checker / separate-authorization workflow. There is no "one user posts, a second user approves" step in the code: a teller op written to TXNPEND is applied immediately when TELLER runs, and a maintenance action in ACCTMNP is applied immediately by ACCTMNT. The manual documents the control model the application does have:

• Append-only journaled ledger (TXNJRNL). Every money movement (D/W/X/I/C) is written as an immutable ledger row carrying a post-transaction running balance and a description, and the file is journaled to TXNJRN (STRJRNPF, IMAGES(*BOTH)) so every WRITE produces a captured before/after image — a full, reconstructable audit trail visible through DSPJRN. This is after-the-fact accountability, not an approval gate.
• Validation gating in the poster. TELLER rejects a posting whose amount exceeds AVLBAL + ODLIM (overdraft-limited withdrawal / the debit leg of a transfer), and rejects an op against an unknown account — counted into the REJECT= total, with the account left untouched. ACCTMNT rejects an open (MTYP='O') whose account number already exists (a CHAIN before WRITE), so a duplicate never overwrites an existing master.
• Holds gate available balance. Open HOLDMST rows reduce AVLBAL via HOLDPOST, so a legal/check hold constrains what a teller can withdraw or transfer without touching the current balance.
• Status gating. Interest accrual, crediting and service charges act only on ASTAT='A' (active) accounts; dormant / closed accounts are skipped.
• Balanced-GL control total. GLPOST only reports its batch IN BALANCE when the batch's DR total equals its CR total, and TRIALRPT / DDABAL independently re-prove DR=CR across the whole ledger — the accounting control that a day's postings reconcile.
• Commitment control on transfers (SQL path). A transfer's two GL legs are atomic on the SQL path: under STRCMTCTL both legs COMMIT together or ROLLBACK together (see F.3). Native record I/O is not under commitment control here.

In sum, the control posture is journaled audit + validation/status gating + a balanced-GL control total + atomic (SQL) transfers, rather than a segregation-of-duties approval workflow.

C. Batch Jobs & the Periodic Cycle ↑ top

DEPOSIT/i's processing is a set of poster and periodic programs rather than one monolithic nightly job: on-demand posters (ACCTMNT maintenance, TELLER teller line, HOLDPOST), a daily accrual (INTACCR), and a month-end / night chain (INTCRED → SVCCHG → GLPOST) plus reporting (STMTGEN, TRIALRPT, DDABAL). None take CALL parameters. The night chain is packaged in the CL driver DBNIGHT, which SBMJOBs each step onto its own night job queue so each step's writes are visible to the next (see quirk PQ-3).

-- DBNIGHT: create the night queue, then submit each step onto it
CRTJOBQ JOBQ(DEPOSIT/NITEQ) TEXT('Deposit night batch')
SBMJOB CMD(CALL DEPOSIT/INTACCR) JOB(DBACCR) JOBQ(DEPOSIT/NITEQ) HOLD(*NO)
SBMJOB CMD(CALL DEPOSIT/INTCRED) JOB(DBCRED) JOBQ(DEPOSIT/NITEQ) HOLD(*NO)
SBMJOB CMD(CALL DEPOSIT/SVCCHG)  JOB(DBSVC)  JOBQ(DEPOSIT/NITEQ) HOLD(*NO)
SBMJOB CMD(CALL DEPOSIT/GLPOST)  JOB(DBGL)   JOBQ(DEPOSIT/NITEQ) HOLD(*NO)

C.1 Full batch program set

Program	Purpose	Reads / writes	Output (DSPLY)	Frequency
ACCTMNT	Apply pending account maintenance: Open / Change status / Re-rate.	Reads ACCTMNP; writes/updates ACCTMST.	ACCTMNT APPLIED=n REJECT=m	On demand.
HOLDPOST	Recompute available balance = current − sum of open holds.	Reads HOLDLF; updates ACCTMST.AVLBAL.	HOLDPOST: available recomputed for n accounts	After hold changes / in DBSETUP.
TELLER	Post deposits / withdrawals / transfers from the pending work file.	Reads TXNPEND; updates ACCTMST; writes TXNJRNL.	TELLER POSTED=n REJECT=m	On demand (teller line).
INTACCR	Accrue one day of tiered interest into ACCRINT for each active account.	Reads INTPLAN; updates ACCTMST.ACCRINT.	INTACCR: accrued interest for n accounts	Daily.
INTCRED	Move accrued interest into the balance, zero ACCRINT, post an 'I' ledger row.	Updates ACCTMST; writes TXNJRNL (TXNID via MAX+1).	INTCRED: credited n accts total t	Month-end.
SVCCHG	Post monthly maintenance fees (unless waived) and flag dormant accounts.	Reads CHGPLAN; updates ACCTMST; writes TXNJRNL ('C').	SVCCHG: fees=n dormant=m	Month-end.
GLPOST	Consolidate ledger activity into balanced DR/CR GL rows; cross-check DR=CR.	Reads TXNJRNL; EXEC SQL INSERT into GLLEDGER.	GLPOST BATCH b IN BALANCE DR=d (or OUT OF BALANCE)	Night / month-end.
TRIALRPT	Print the GL trial balance from GLLEDGER (SQL cursor), prove DR=CR.	Reads GLLEDGER; spools TRIALPR.	TRIALRPT rows=n DR=d CR=c	Night / month-end.
STMTGEN	Print each account's statement/passbook register (running balance).	Reads ACCTMST/CUSTMST/TXNLF; spools STMTPR.	STMTGEN: printed n register lines	Statement cycle.
DDABAL	ILE COBOL: total ledger balance by product (COMP-3 FD), cross-check GL deposit liability.	Reads ACCTMST; EXEC SQL SUM over GLLEDGER.	DDABAL SAVINGS.. CHECKING.. TOTAL.. GL NET DEPOSIT LIABILITY..	Reconciliation.

C.2 Teller / daily / month-end detail

Teller — TELLER

Reads the current high-water TXNID once at entry (EXEC SQL SELECT COALESCE(MAX(TXNID),0)) and advances a local counter per WRITE (quirk PQ-3: a program's own native WRITEs are not visible to its same-program embedded SQL, so per-row MAX+1 would collide on the UNIQUE key). Then per pending op: deposit credits CURBAL+AVLBAL and writes a 'D' row; withdrawal is rejected if PAMT > AVLBAL + ODLIM, else debits and writes 'W'; transfer debits the FROM account (writes TRANSFER OUT) then credits the TO account (writes TRANSFER IN) — two ledger rows, one balanced double-entry.

Expected DSPLY (dep + wd + transfer(2 legs) + dep, with 2 overdraft rejects):
  TELLER POSTED=5 REJECT=2   5 ledger rows written, 2 ops rejected

Daily — INTACCR

For each ASTAT='A' account: pick band B when CURBAL ≥ 10000.00 else band A, CHAIN (PRODCD:BAND) into INTPLAN (falling back to band A if the tier is missing), and if a tier is found with FACTOR > 0, accrue one day's simple interest ACCRINT += CURBAL × (FACTOR / 365) in packed-decimal math and UPDATE. Savings earns; the 0%-rate checking product accrues nothing. INTACCR posts no ledger row (it only grows the ACCRINT bucket).

Expected packed-decimal accrual (band A, 5000 @ 2.5% APY, one day):
  ACS0000001 ACCRINT ~= 5000 * 0.025 / 365 = 0.3425   (11P4, < $1/day)
  ACS0000003 (25000, band B @ 3.5%) accrues MORE than band A
  ACC0000002 (checking, 0%) accrues 0

Month-end — INTCRED, then SVCCHG, then GLPOST

INTCRED: for each active account with ACCRINT ≥ 0.01, add the accrued interest to CURBAL+AVLBAL, zero ACCRINT, and write an 'I' INTEREST CREDIT ledger row (TXNID from MAX+1 advanced locally). SVCCHG: for each active account, CHAIN its CHGPLAN; if the fee is positive and CURBAL < WAIVBAL, debit the MFEE and write a 'C' SERVICE CHARGE row; then, independently, if LSTACT < cutoff (20251001), set ASTAT='D' (dormant). GLPOST: sum the ledger by type, then post the double-entry legs (deposits DR 1000-CASH / CR 2000-DEPL; withdrawals reverse; interest DR 5000-INTX / CR 2000-DEPL; fees DR 2000-DEPL / CR 4000-FEEI; transfers net within 2000-DEPL), then cross-check the batch DR total equals its CR total.

Expected DSPLY (month-end chain):
  INTCRED: credited 2 accts total 0.68
  SVCCHG: fees=1 dormant=1        ACC0000004: 300 - 8 fee = 292, then flagged D
  GLPOST BATCH 1 IN BALANCE DR=...  batch DR total = CR total

C.3 Ordering & dependencies

• HOLDPOST after hold changes. Available balance is only correct after HOLDPOST recomputes it; DBSETUP runs it once after seeding so the seeded legal hold (2000 on ACS0000003) reduces available to 23000.
• ACCRUE (INTACCR) before CREDIT (INTCRED). Crediting moves the accrued bucket into the balance, so daily accrual must have run for the period first or interest is under-credited.
• Postings before GLPOST. GLPOST summarises the ledger, so all of the day's teller/interest/charge rows must be written before it runs; the night chain orders INTACCR→INTCRED→SVCCHG→GLPOST for exactly this reason.
• GLPOST before TRIALRPT / DDABAL. The trial balance and the COBOL cross-check read GLLEDGER, so the GL feed must be posted before they can prove DR=CR.
• Each night step its own SBMJOB (PQ-3). Steps run as separate submitted jobs so one step's native writes are committed and visible to the next; the day-cycle test waits for each job to reach OUTQ before asserting.

D. Data Files (data dictionary) ↑ top

All files are in library DEPOSIT, grounded in the DDS/SQL members in src/sources.mjs. Money is packed decimal (11P 2); accrued interest is 11P 4; interest rates are 5P 4 (0.0250 = 2.50% APY) and tier factors 7P 5; dates are stored as zoned 8S 0 in YYYYMMDD form.

CUSTMST — Customer master (K CUSTNO, UNIQUE)

Field	Type	Meaning
CUSTNO	6A	Customer number (key).
CNAME	25A	Customer name.
ADDR / CITY / ST / ZIP	20A / 15A / 2A / 5A	Address components.
OPNDT	8S 0	Customer open date (YYYYMMDD).

ACCTMST — Account master (K ACCTNO, UNIQUE)

Field	Type	Meaning
ACCTNO	10A	Account number (key), e.g. ACS0000001 (S) / ACC0000002 (C).
ACUSTNO	6A	Owning customer (→ CUSTMST).
PRODCD	1A	Product: S savings, C checking/DDA.
ASTAT	1A	Status: A active, D dormant, X closed.
CURBAL	11P 2	Current (ledger) balance.
AVLBAL	11P 2	Available balance = current − open holds.
ACCRINT	11P 4	Accrued-unpaid interest bucket (4dp).
INTRATE	5P 4	Account interest rate (0.0250 = 2.50% APY).
ODLIM	9P 2	Overdraft limit (extends withdrawable available).
CHGCD	2A	Service-charge plan code (→ CHGPLAN).
AOPNDT / LSTACT	8S 0	Account open date / last-activity date (drives dormancy).

TXNJRNL — Teller transaction ledger (K TXNID, UNIQUE, journaled)

Field	Type	Meaning
TXNID	9S 0	Arrival-sequence transaction id (key).
TACCTNO	10A	Account posted to.
TXNTYPE	1A	D deposit, W withdrawal, X transfer, I interest, C charge.
TXNDT	8S 0	Transaction date (YYYYMMDD).
TXNAMT	11P 2	Transaction amount.
RUNBAL	11P 2	Running balance AFTER this posting (passbook idiom).
DESCR	20A	Posting description, e.g. TRANSFER IN.

Logical TXNLF (PFILE(TXNJRNL)) keys the same rows by TACCTNO then TXNID — the passbook/register access path used by REGINQ and STMTGEN.

HOLDMST — Holds (K HACCTNO, HLDSEQ, UNIQUE)

Field	Type	Meaning
HACCTNO / HLDSEQ	10A / 2S 0	Account + hold sequence (composite key).
HLDAMT	11P 2	Held amount (reduces available when open).
HLDEXP	8S 0	Hold expiry date.
HSTAT	1A	Hold status: O open (counted by HOLDPOST).
HDESC	20A	Hold description, e.g. LEGAL HOLD.

Logical HOLDLF (PFILE(HOLDMST)) keyed by HACCTNO — the per-account access path HOLDPOST sums.

INTPLAN — Interest rate tiers (K PRODCD, BAND, UNIQUE)

Field	Type	Meaning
PRODCD / BAND	1A / 1A	Product + band (A base, B high-balance) (key).
MINBAL	11P 2	Minimum balance for the band.
FACTOR	7P 5	Annual rate (0.02500 = 2.5% APY); daily rate = FACTOR / 365.

Seeded tiers: S/A 0→0.02500, S/B 10000→0.03500, C/A 0→0.00000 (checking earns nothing).

CHGPLAN — Service-charge plans (K CHGCD, UNIQUE)

Field	Type	Meaning
CHGCD	2A	Charge plan code (key), matched from ACCTMST.CHGCD.
MFEE	7P 2	Monthly maintenance fee.
WAIVBAL	11P 2	Minimum balance that waives the fee.
CDESCR	20A	Plan description.

Seeded plans: S1 fee 2.00 / waive 1000.00; C1 fee 8.00 / waive 2500.00.

TXNPEND — Pending teller-op work file (arrival sequence)

Field	Type	Meaning
PSEQ	5S 0	Arrival sequence.
PTYP	1A	Op type: D deposit, W withdrawal, X transfer.
PFRM / PTO	10A / 10A	From/primary account; to account (transfer only).
PAMT	11P 2	Amount to post.

ACCTMNP — Pending account-maintenance work file (arrival sequence)

Field	Type	Meaning
MSEQ	5S 0	Arrival sequence.
MTYP	1A	Action: O open, C change status, R re-rate.
MACCT	10A	Account being maintained.
MCUST / MPROD / MCHG	6A / 1A / 2A	Customer / product / charge-plan (open only).
MNSTAT	1A	New status A/D/X (change only).
MRATE	5P 4	New interest rate (re-rate).
MBAL	11P 2	Opening balance (open only).

GLLEDGER — General-ledger feed (DB2 table)

Field	Type	Meaning
BATCHID	INTEGER	GL batch number (from MAX(BATCHID)+1).
ACCT	CHAR(10)	GL account: 1000-CASH, 2000-DEPL, 4000-FEEI, 5000-INTX.
DRCR	CHAR(1)	D debit / C credit.
AMT	DECIMAL(13,2)	Leg amount.
SRCPGM	CHAR(10)	Source program (e.g. GLPOST).

Relationships

• ACCTMST.ACUSTNO → CUSTMST.CUSTNO (an account belongs to a customer; not a declared FK — chained in RPG).
• TXNJRNL.TACCTNO → ACCTMST.ACCTNO (per-account ledger; TXNLF is the keyed access path).
• HOLDMST.HACCTNO → ACCTMST.ACCTNO (holds against an account; HOLDLF is the keyed access path).
• ACCTMST.CHGCD → CHGPLAN.CHGCD (which fee plan applies).
• INTACCR joins ACCTMST to INTPLAN by (PRODCD:BAND), band chosen from CURBAL.
• GLLEDGER is an aggregate ledger keyed by BATCHID (no per-account-master FK).
• TXNPEND / ACCTMNP are transient work files consumed by TELLER / ACCTMNT.

E. Operations Runbook ↑ top

E.1 Day-in-the-life

1. Apply any account maintenance: load actions into ACCTMNP, then CALL DEPOSIT/ACCTMNT; confirm ACCTMNT APPLIED=n REJECT=m.
2. If holds changed, CALL DEPOSIT/HOLDPOST to recompute available balances.
3. Post the teller line: load ops into TXNPEND, then CALL DEPOSIT/TELLER (or SBMJOB it); confirm TELLER POSTED=n REJECT=m.
4. Handle inquiries interactively through CALL DEPOSIT/TELMENUP (option 1 = account inquiry, option 2 = register).
5. Run the daily accrual: SBMJOB CMD(CALL DEPOSIT/INTACCR).
6. Print statements/trial balance as needed: CALL DEPOSIT/STMTGEN, CALL DEPOSIT/TRIALRPT.

Pre-checks: confirm the job's library list includes DEPOSIT; confirm the pending work files (TXNPEND/ACCTMNP) hold the intended rows before running the poster.

Post-checks after teller/accrual:

• TELLER POSTED= count = 1 row per deposit/withdrawal + 2 per transfer; rejects are overdraft/unknown-account ops that left the master untouched.
• Each posted account's CURBAL/AVLBAL reconcile, and each TXNJRNL row's RUNBAL equals the post-transaction balance.
• Transfers wrote a TRANSFER OUT and a TRANSFER IN row of equal amount (balanced double-entry).
• INTACCR grew ACCRINT for active interest-bearing accounts only (band B for CURBAL≥10000); the 0%-rate checking product accrued nothing.
• Every ledger WRITE was journaled — verify with DSPJRN JRN(DEPOSIT/TXNJRN) FILE(DEPOSIT/TXNJRNL) (single-paren form; see F.3).

E.2 Month-end close

1. Confirm the month's daily INTACCR runs are complete (accrued interest is up to date).
2. Submit the night chain: CALL DEPOSIT/DBNIGHT (or the four SBMJOBs manually), which runs INTCRED → SVCCHG → GLPOST in order on DEPOSIT/NITEQ.
3. Confirm each step: INTCRED: credited n accts, SVCCHG: fees=n dormant=m, GLPOST BATCH b IN BALANCE.
4. Prove and reconcile the GL:

SELECT SUM(CASE WHEN DRCR='D' THEN AMT ELSE 0 END) AS DR,
       SUM(CASE WHEN DRCR='C' THEN AMT ELSE 0 END) AS CR
  FROM DEPOSIT.GLLEDGER;

Reconciling figures (the same ones the day-cycle and interest suites assert):

• GL in balance — SUM(DR) = SUM(CR) and > 0. GLPOST logs its batch IN BALANCE; TRIALRPT prints TRIAL BALANCE IN BALANCE DR=CR=....
• Interest expense — the interest credited by INTCRED appears as a DR to 5000-INTX (CR to 2000-DEPL) in the GL.
• Fee income — each SERVICE CHARGE row nets DR 2000-DEPL / CR 4000-FEEI; e.g. ACC0000004 300 − 8 fee = 292, then flagged dormant.
• Ledger vs GL — DDABAL totals the account master by product (COMP-3 FD) and reports the net GL deposit liability from SUM(CASE WHEN DRCR='C' THEN AMT ELSE -AMT END) over 2000-DEPL, the accounting cross-check between the operational store and the GL.

Statement cycle: CALL DEPOSIT/STMTGEN spools one STMTPR passbook register per account (one DETAIL line per ledger txn, an END OF ACCOUNT total line, paginated past the 66-line page via OVRFLW).

E.3 Failure & re-run rules

Each program DSPLYs a one-line result to the joblog; the SQL programs (GLPOST/TRIALRPT) additionally report IN BALANCE / OUT OF BALANCE. A healthy month-end ends with a balanced GL.

Situation	Behaviour	Action
Overdraft-rejected teller op	TELLER increments REJECT=, leaves the account untouched, writes no ledger row.	Correct the amount (or the overdraft limit) and re-post only the failed op — already-posted ops are consumed.
Duplicate account open	ACCTMNT rejects an MTYP='O' whose MACCT already exists (CHAIN before WRITE); existing master unchanged.	Rejected count is expected; fix the account number to open a genuinely new one.
Re-run INTACCR same day	Not idempotent — each run accrues another day into ACCRINT.	Run INTACCR exactly once per business day; a duplicate over-accrues. Correct by re-seeding / adjusting before crediting.
Re-run INTCRED	Credits only accounts with ACCRINT ≥ 0.01; after crediting, ACCRINT=0 so a second run is a no-op.	Naturally idempotent once accrual is zeroed — safe to re-run.
Re-run SVCCHG same month	Not idempotent — posts another fee to still-low-balance accounts.	Run once per month; do not resubmit. A dormancy flag re-set is harmless (already D).
GLPOST OUT OF BALANCE	Batch DR total ≠ CR total (a data / posting problem).	Investigate the batch's rows in GLLEDGER WHERE BATCHID=b; the double-entry legs per type should net.
Night step fails partway	Each step is a separate SBMJOB; a later step may not have run.	Re-submit the failed step; because steps are ordered on the queue, confirm each reaches OUTQ before the next (PQ-3).
DSPJRN shows Entries:0	The list/double-paren FILE((lib obj)) form returns no entries (PG5-401).	Use the single-paren form: DSPJRN JRN(DEPOSIT/TXNJRN) FILE(DEPOSIT/TXNJRNL).

F. Developer Reference ↑ top

The complete program surface, from src/sources.mjs. All objects are in library DEPOSIT; the build/seed path is DBSETUP (CL) → seedDeposit() (src/seed.mjs) which loads each member into QDDSSRC/QRPGLESRC/ QCBLLESRC/QCLSRC/QSQLSRC.

F.1 Programs (13 RPG + 1 COBOL)

SEEDDATA (RPGLE)

Loads 3 customers, 4 accounts, 3 interest tiers, 2 charge plans and 1 legal hold; called by DBSETUP.

ACCTMNT (RPGLE)

Reads ACCTMNP; per MTYP: Open (CHAIN-guard against duplicate, then WRITE a UNIQUE-keyed master — escapes PHASE22-1), Change status, Re-rate. At most one UPDATE per read record, re-CHAINing for a fresh read (escapes PHASE22-2). Nested IF, not elseif (PQ-1).

HOLDPOST (RPGLE)

For each account, sum open HOLDLF rows and set AVLBAL = CURBAL − hsum.

TELLER (RPGLE + SQL)

Reads TXNPEND; deposit / withdrawal (overdraft-checked) / transfer (two legs). TXNID from MAX(TXNID) read once then advanced by a local counter (PQ-3). Writes TXNJRNL with running balance.

INTACCR (RPGLE)

Tiered daily accrual: band from CURBAL, CHAIN (PRODCD:BAND) INTPLAN (PQ-2), ACCRINT += CURBAL × FACTOR/365 in packed decimal.

INTCRED (RPGLE + SQL)

Month-end: move ACCRINT into balance, zero it, write an 'I' ledger row.

SVCCHG (RPGLE + SQL)

Post 'C' maintenance fee unless CURBAL ≥ WAIVBAL; independently flag ASTAT='D' when LSTACT < cutoff. Re-CHAINs between the two UPDATEs (PQ-9).

GLPOST (RPGLE + SQL)

Sum the ledger by type, insert balanced DR/CR legs into GLLEDGER, cross-check batch DR=CR.

STMTGEN (RPGLE, PRTF)

Per-account passbook/statement register over TXNLF, forcing a page overflow (OFLIND(*INOF)).

TRIALRPT (RPGLE + SQL, PRTF)

SQL cursor over GLLEDGER ordered by batch/account/DRCR; prints each row and a DR=CR total line.

ACCTINQ (RPGLE, WORKSTN)

Plain EXFMT ACCTINQF account inquiry: chain master + customer, render product/status/balances.

REGINQ (RPGLE, WORKSTN + SFL)

SFL/SFLCTL register: clear (33), load one REGSFL row per TXNLF txn by RRN, EXFMT REGCTL.

TELMENUP (RPGLE, WORKSTN)

Menu EXFMT MENUFMT; indicator-conditioned fixed-form CALL 'ACCTINQ' / CALL 'REGINQ' (PQ-1).

DDABAL (ILE COBOL + SQL)

Reads ACCTMST via a COMP-3 FD (zoned 8S 0 dates as PIC S9(8) DISPLAY, PQ-6); totals savings/checking ledger balances; EXEC SQL computes net GL deposit liability from GLLEDGER.

F.2 Embedded-SQL patterns

The RPG and COBOL programs use these embedded-SQL idioms against the DB2 layer:

• SELECT MAX INTO — read the next id/batch once at entry, e.g. exec sql select coalesce(max(TXNID),0) into :ntid from DEPOSIT.TXNJRNL; then advance a local counter (PQ-3).
• INSERT literal rows — the balanced GL legs, e.g. exec sql insert into DEPOSIT.GLLEDGER values(:bat,'1000-CASH','D',:gdep,'GLPOST');
• Aggregate cross-check — a CASE sum to prove DR=CR per batch, e.g. select coalesce(sum(case when DRCR='D' then AMT else 0 end),0) ... into :drtot ... where BATCHID = :bat;
• DECLARE / OPEN / FETCH cursor — TRIALRPT reads GLLEDGER ordered by batch/account, looping dow sqlcod = 0.
• COBOL COPY SQLCA + EXEC SQL — DDABAL mixes a native COMP-3 FD read with an EXEC SQL SELECT ... INTO :GL-DEPL END-EXEC.
• RUNSQL under commitment control — the transfer atomicity proof INSERTs both GL legs with COMMIT(*CHG), then ROLLBACK (both vanish) or COMMIT (both persist).

F.3 Journaling & commitment control

Journaling. DBSETUP creates the receiver TXNRCV and journal TXNJRN, then STRJRNPF FILE(DEPOSIT/TXNJRNL) JRN(DEPOSIT/TXNJRN) IMAGES(*BOTH). Every RPG WRITE/UPDATE to the ledger is captured as an R/PT (record-put) entry stamped with the posting job; jrn.entries() and DSPJRN both surface them. Use the single-paren FILE(DEPOSIT/TXNJRNL) form of DSPJRN — the double-paren list form returns Entries:0 (PG5-401).

Commitment control. Honored on the SQL/RUNSQL path only, not native record I/O (PQ-5). So the transfer's atomicity is proven on the GL: STRCMTCTL LCKLVL(*CHG), two RUNSQL ... COMMIT(*CHG) INSERTs of the DR and CR legs, then ROLLBACK (row count returns to baseline — both legs discarded) or COMMIT (both persist), then ENDCMTCTL. The native TELLER two-leg transfer relies instead on the journaled ledger for reconstructability.

F.4 Platform quirk points (PQ)

The source is written to sidestep several documented emulator behaviours; these are the ones that shape the application code and matter to a maintainer:

PQ	Behaviour	How the app handles it
PQ-1	Free-form elseif can mis-scope the trailing END-IF.	Nested if/else throughout (TELLER, ACCTMNT, TELMENUP).
PQ-2	Free-form CHAIN can't reference a fixed-form named KLIST.	Parenthesised composite key: chain (prodcd:band) intr; (INTACCR).
PQ-3	A program's own native WRITEs aren't visible to its same-program embedded SQL; SBMJOB writes visible to the next step only across jobs.	Read MAX(id) once, advance a local counter; night chain uses one SBMJOB per step.
PQ-4	PRTF field-position digits are column-sensitive (end at DDS col 44).	STMTPR / TRIALPR field positions authored accordingly.
PQ-5	Commitment control / ROLLBACK honored on the SQL path, not native record I/O.	Transfer atomicity proven via RUNSQL on GLLEDGER.
PQ-6	Zoned nS 0 fields map to COBOL PIC S9(n) DISPLAY, not COMP-3.	DDABAL FD maps AC-OPNDT/AC-LSTACT as DISPLAY.
PQ-8	*EXCLUDE + *USE-only on a batch-written file can throw SFF9802 even for a privileged user.	Adopted authority: USRPRF(*OWNER) program lets a weak profile post to the *PUBLIC *EXCLUDE ledger; the same program without it is denied.
PQ-9	PHASE22-2: a second UPDATE of the same read record can be dropped.	SVCCHG re-CHAINs before the dormancy UPDATE so both the fee and the flag persist.

G. Glossary ↑ top

Accrual (interest accrual)

Recognising interest earned each day on the current balance, added to the ACCRINT bucket. Here: simple daily interest, 365-day convention, CURBAL × FACTOR/365 (INTACCR), in packed decimal.

Available balance

AVLBAL = current balance minus the sum of open holds (HOLDPOST). Withdrawals/transfers are limited to AVLBAL + ODLIM.

Band (rate band)

A within-product interest tier in INTPLAN: band A base, band B for high balances (CURBAL ≥ 10000). INTACCR chooses the band from the balance.

Crediting (interest crediting)

Moving the accrued-interest bucket into the balance at month-end and posting an 'I' ledger row (INTCRED), then zeroing ACCRINT.

DDA / demand deposit

A demand-deposit account (checking/savings) whose balance is payable on demand — the line of business DEPOSIT/i models.

Dormancy

Flagging an account inactive (ASTAT='D') when its last activity date predates a cutoff (SVCCHG). Dormant accounts are skipped by the interest/charge passes.

Double-entry / DR=CR

Every GL posting has equal debit and credit legs; a batch is "in balance" when SUM(DR)=SUM(CR) (GLPOST / TRIALRPT / DDABAL).

Hold

A claim (check hold / legal hold) that reduces available balance without changing the current balance (HOLDMST, applied by HOLDPOST).

Journaling

Capturing before/after images of every change to a file. The ledger TXNJRNL is journaled (STRJRNPF IMAGES(*BOTH)) to TXNJRN, viewable via DSPJRN.

Overdraft limit (ODLIM)

An amount by which a withdrawal/transfer may exceed the available balance before it is rejected.

Packed decimal (nPd)

The IBM i money/number encoding used by ACCTMST/TXNJRNL (11P 2) and the accrual math (11P 4).

Passbook / register

The per-account list of transactions with a running balance (the TXNLF access path; rendered by REGINQ and STMTGEN).

Running balance (RUNBAL)

The account balance immediately after a posting, stored on each ledger row so the register/statement reads like a passbook.

SBMJOB / *JOBQ

Submit Job onto a job queue — the night chain (DBNIGHT) submits each batch step onto DEPOSIT/NITEQ so its writes are visible to the next step.

Service charge

A monthly maintenance fee (CHGPLAN) posted as a 'C' ledger row unless the minimum-balance waiver applies (SVCCHG).

SFL / subfile

A 5250 display construct listing many rows on one screen (DDS SFL/SFLCTL). REGINQ's account register is a subfile.

Transfer (two-leg)

Moving funds between accounts as a debit leg (TRANSFER OUT) on the from-account and an equal credit leg (TRANSFER IN) on the to-account — one balanced double-entry (TELLER).

Work file (pending file)

An arrival-sequence PF (TXNPEND, ACCTMNP) holding requested actions that a poster program (TELLER, ACCTMNT) reads and applies — the classic AS/400 batch idiom.