Acorn Statement of Year 2000 Conformity --------------------------------------- Acorn has chosen to produce a statement of year 2000 conformity based upon the definition DISC PD2000-1 produced by the British Standards Institute; the BSI definition is reproduced below by kind permission of its authors, the BSI DISC office. DISC PD2000-1 A Definition of Year 2000 Conformity Requirements A DEFINITION OF YEAR 2000 CONFORMITY REQUIREMENTS THE DEFINITION Year 2000 conformity shall mean that neither performance nor functionality is affected by dates prior to, during and after the year 2000. In particular: Rule 1. No value for current date will cause any interruption in operation. Rule 2. Date-based functionality must behave consistently for dates prior to, during and after year 2000. Rule 3. In all interfaces and data storage, the century in any date must be specified either explicitly or by unambiguous algorithms or inferencing rules. Rule 4. Year 2000 must be recognised as a leap year. AMPLIFICATION OF THE DEFINITION AND RULES General Explanation Problems can arise from some means of representing dates in computer equipment and products and from date-logic embedded in purchased goods or services, as the year 2000 approaches and during and after that year. As a result, equipment or products, including embedded control logic, may fail completely, malfunction or cause data to be corrupted. To avoid such problems, organisations must check, and modify if necessary, internally produced equipment and products and similarly check externally supplied equipment and products with their suppliers. The purpose of this document is to allow such checks to be made on a basis of common understanding. Where checks are made with external suppliers, care should be taken to distinguish between claims of conformity and the ability to demonstrate conformity. Rule 1. 1.1 This rule is sometimes known as general integrity. 1.2 If this requirement is satisfied, roll-over between all significant time demarcations (e.g. days, months, years, centuries) will be performed correctly. 1.3 Current date means today's date as known to the equipment or product. Rule 2. 2.1 This rule is sometimes known as date integrity. 2.2 This rule means that all equipment and products must calculate, manipulate and represent dates correctly for the purposes for which they were intended. 2.3 The meaning of functionality includes both processes and the results of those processes. 2.4 If desired, a reference point for date values and calculations may be added by organisations; e.g. as defined by the Gregorian calendar. 2.5 No equipment or product shall use particular date values for special meanings; e.g. "99" to signify "no end value" or "end of file" or "00" to mean "not applicable" or "beginning of file". Rule 3. 3.1 This rule is sometimes known as explicit/implicit century. 3.2 It covers two general approaches: (a) explicit representation of the year in dates: e.g. by using four digits or by including a century indicator. In this case, a reference may be inserted (e.g. 4-digit years as allowed by ISO standard 8601:1988) and it may be necessary to allow for exceptions where domain-specific standards [e.g. standards relating to Electronic Data Interchange, Automatic Teller Machines or Bankers Automated Clearing Services] should have precedence. (b) the use of inferencing rules: e.g. two digit years with a greater value than 50 imply 19xx, those with a value equal to or less than 50 imply 20xx. Rules for century inferencing as a whole must apply to all contexts in which the date is used, although different inferencing rules may apply to different data sets. General Notes For Rules 1 and 2 in particular, organisations may wish to specify allowable ranges for values of current date and dates to be manipulated. The ranges may relate to one or more of the feasible life-span of equipment or products or the span of dates required to be represented by the organisation's business processes. Tests for specifically critical dates may also be added (e.g. for leap years, end of year, etc). Organisations may wish to append additional material in support of local requirements. Where the term century is used, clear distinction should be made between the "value" denoting the century (e.g. 20th) and its representation in dates (e.g. 19xx); similarly, 21st and 20xx. This definition of Year 2000 conformity has been produced with the permission of the authors, the British Standards Institution. It was produced by the BSI committee BDD/1/-/3 in response to demand from UK industry, commerce and the public sector. Acorn Statement of Year 2000 Conformity --------------------------------------- Introduction ------------ This document describes the degree of conformity of the Acorn components listed in Schedule 1 to the BSI document DISC PD2000-1, "A Definition of Year 2000 Conformity Requirements". It is intended to be read in conjunction with said BSI document. Rule 1 Compliance ----------------- The components listed in Schedule 1 are conformant to the General Integrity rules 1.1, 1.2 and 1.3 provided that: * The "current date" is defined as today's date in the Gregorian calendar and no other calendar. * "Today's date" falls in the range detailed in the Rule 2 Compliance note below. Rule 2 Compliance ----------------- The components listed in Schedule 1 are conformant to the Date Integrity rules 2.1 through 2.5 inclusive subject to the following limitations: The baseline reference point for date compliance is the date of adoption of the Gregorian calendar or Gregorian January 1st 1900 AD, whichever is the later. In the case of localisation to other territories which adopted the Gregorian calendar on a date other than the date of the UK adoption of the Gregorian calendar, the baseline reference point for date correctness should be taken as the Gregorian date in that locale on which the Gregorian calendar was last adopted (this takes into account those territories which adopted the Gregorian calendar, renounced it, and then later re-adopted it). For the systems described in Schedule 1 only the UK territory is officially supported, although unofficial alternative territory definitions exist. In reference to the General Notes section of the BSI document, we declare a date ceiling relating to the projected feasible lifespan of the equipment. Dates will cease to be represented correctly in the Gregorian year 2248 AD, hence the chosen declared ceiling for correct date representation is Gregorian December 31st, 2247 AD. In Rule 2.2, calculation, manipulation and representation of dates is only guaranteed conformant for Gregorian dates in the range above (subject to the Additional Notes below). In Rule 2.3, only the ROM-based OS software and system hardware detailed in Schedule 1 is guaranteed to represent process results in a compliant manner (subject to the Additional Notes below). Rule 3 Compliance ----------------- The components listed in Schedule 1 are conformant to the Explicit / Implicit Century rules 3.1 and 3.2 subject to the Additional Notes below. All components listed in Schedule 1 store the year in a 4-digit format. Similarly, files written to filing systems which intrinsically support a four year-digit file datestamping system (such as Acorn ADFS) and for which suitable interfacing software (such as RISC OS FileCore) exists will have their datestamp recorded with a four-digit year component. It is possible to specify years in two-digit form when passing arguments to the system calls SWI "Territory_ConvertTimeStringToOrdinals" (with reason codes 2 and 3) and SWI "OS_Word",15 (with reason codes 15 and 24, which specify that the operation to be performed is a write to CMOS); in the case of these specific calls, dates supplied as arguments and which contain a two-digit year field are treated as follows: 0