| 摘要 |
<p>1,255, 441. Marginal testing of logic units. CONTROL DATA CORP. Jan. 27, 1970 [Feb. 18, 1969], No.3884/70. Heading G1U. In a system for "marginal testing" a plurality of logic modules 101, Fig. 2, each including its own source of reference voltage, for example from a potential divider 212, 213, each logic module is associated with a bi-directional current switch 220, and means are provided for selecting one of the bi-directional current switches and for causing it either to raise or to lower the reference voltage applied to the associated logic module, e.g. by injecting current into, or extracting current from, the junction 215 of the potential divider. As described 4096 logic modules, such as 101, Fig. 2, and forming part of a computer, are arranged in 16 chassis or cabinets Fig. 3, each of which is divided into four quadrants each containing an 8 x 8 array of logic modules. Selection of a particular logic module is by a 12-bit word 301, Fig. 3, six bits selecting 303 a particular quadrant, and the remaining bits, in two groups of three, selecting a row and a column within a quadrant. Each quadrant has an associated control circuit Fig. 5, one of which is selected by marking its lead 418, and to all of which are applied inverse signals 419a, 419b, indicating whether the reference voltage is to be raised or lowered. As a result the selected control circuit marks either a "high" or a "low" lead 412, 422, which marking is applied Fig. 4 to a corresponding group of 64 voltage margin driver circuits, Fig. 6, (not shown) each of which includes a bi-directional current switch as shown at 220 in Fig. 2. The voltage margin driver circuits Fig. 4 also receive decoded row and column signals, so that only one voltage margin driver circuit is activated either to inject current into, or to extract current from, the junction 215, Fig. 2, of the potential divider reference voltage source of the associated logic module, thereby either raising or lowering the reference voltage applied to that logic module. Once the reference voltage applied to a selected logic module has been varied, a diagnostic programme is run in order to detect any incipient faults in the system.</p> |
